It is technically possible but has not been designed thatr way, as in 19th century, some nations were way "more equals than others"
therefoere you have the top 8 actors basically
in an historical (I mean historically plausible) game :
Ottoman and China are unable to industrialize (enough) for complex but commiting social/cultural/institutionnal reasons, factored in gameand simplified - if conditions are eased, it is a departure from historixc reality, you are less placed in the situation with constraionts of your historical counterpart (you work basically with fellah, coolies, poor peasants, not hyper trained 20th century workers or even educated Prussian ones beklieve me, it is something difficult with Russia, japan, Italy, so China Ottoman and Guatemala - it is not a "fate of the sky")
in 19th century China fate is to be dismembered as unable to oppose technically Russia, France, Britain, others and even late industrialized japan in time - it's a matter of organization, firepower, industrial might, China could certainly compete in 16th century, can sure right now, had no way to give a match in 19th century -
else you live in a fantasy world where imperial system does not exist, rebels are not beheaded, and population has the cultural and productivity level of present day China .. or "if My chinese were martians with alien technology")
only way not being dismembered is having THE POWERS (les puissances = the GREAT powers - a small club when you are approved by your peers only) not agreeing and the resulting balance preserve you for utter carving
you can have a wonderful and ULTRA CHALLENGING game experience fighting this against all odds, and if you keep constraints and get a good result, it is a remarkable and rewarding achievement
but else, it is not a glamorous role for most players, rather unrewarding (compare with European, American or even Jaopanese expansionnism)
and of course it is impossible to cover 100ù of the real world, ever
ditto Ottoman :
fate of ottoman is to be regularly crushed by the more powerful and (even them) more modern Russia, offer sometimes a stand and a good match, but be saved ONLY by "cavalry" of powerful (they) friends ("les puissances", the powers, club of which you don't and won't belong - they will sometimes even invite you to a backseat of a conference, just to WATCH them decide- without your opinion of your fate and potential carving) which will be according time span, France, Britain, somehow Austria, and Germany. normally, except if you are lucky enough to have Russia bled white by other powers, you lose. of course you can resist better than AI by micromanagement, sound military play, and acutre diplomatic opportunity, but basically
- either you are on defence
- or you crush revolts
you are no longer on Soleiman times - you have a defnsive play, worse even than Austria's (whio can crush Italy or Serbia on her own) - that can be a wonderful test of skills against a usually not technologically on the top foe, where you'll use climate and logistics at your best. but strategic prospects will look frustrating to many.
If you play Belgium then you're a very modern state (gee

) BUT you owe your survival to agreement of other powers - you can't survive alone against France or germany. Congo is yours BECAUSE other powers balance accpted so, not because you could defend it*. in a fiormer version of game, before AI.Diplobias and with a too agressive setting, weird chaotic agressivity made belgium hopelessly invaded - ceding Luxemburg to Prussia may spoil your fun in short order. now AI shouldn't do that (still beware napoleon III and pangermanists) but it may be frustrating role though. If you're in a multiplayer game..pray you have balance minded fellow players.
*see historical Portugal example, who had to back down when they collided with british schemes, and was subject of intense Anglo german talks, and happy enough for Portuguese Angola and Mozambique those talks failed
once again it's a matter of means - Portugal can't compete with Britain and Germany as well i don't believe herreros can compete with portugal (one can play the herreros too)
Spain is an interesting case, besides USA in 1898 they have no natural powerful predators- they can colonize a bit with profit (Morocco and western sahara, but is all) BUT they don't normally stand a chance against the US giant - I say normally because you will be saved by fact tghat in PRESENT version AI usually don't build any modern ships (as a player, you know better, and could win your battles),
- now facing a player- run US, a realistic US military .... he has all you don't have, superior population, technology, economy, coal, try to fight barehands a man with a kalachnikov .... at 100 meters in open ground

ditto for Confederate (can hold, fate is to disappear, you can technically play Taipings too ..), or Mexico (lost california and texas to USA, lost another one, was invaded by France who went away
only when instructed to do so
by USA , who, after having dispatched Dixie, "expressed the opinion" Americas were
their private backyard, which was good enough realistically then (see Monroe and Roosevelt corollary, plus more pressing neighbours at french borders - did i say preuszen ?)
I mean ALL those countries may be fun to play if you like challenge
ALL are playable (see how on forums)
but most were not developed because they would be considered as unrewarding in a realistic context
not that you shouldn't play them - you can !
but, say "mexico" technology, literacy rate, and political unstability (France was switzerland in comparison) are realistically
implicitly incorporated into mexico possibility
so game of
main actors has been developed more - "preys" less
that is the philmosophy of the thing, it reflexes the real 19th century
so game is designed to give
best experience, richest , with most powerful
Powersbecause it is a realistic game,
aims to put you in your historical counterparts shoes/boots, with accurate opportunities and constraintsIt can be played with any nation at your wishhope it helps
cheers