All my victories in the provinces earned only 1% of XP
You can now see the exact ampunt of exp ypu have. So next province, check your before and after to see if you got the correct amount.
I would guess you’re getting smaller percentages due to being a higher level and needing more exp
yes, at higher levels, doing province stage maps, particularly lower level ones like 8-7 or 12-6 will give <1% of the total XP.
For example to get to level 27, you need 331,474 XP. Stage 8-7 gives 817 XP, which is only 0.25% (e.g. you need to do that map 4 times to get 1% of the xp for next level).