Turns out many parts on my used KTM has to be replaced. Need suggestions

I had a few good rides with it, I felt it’s not perfect, but I was enjoying riding again.

I’ve looked up a few things nowdays, decided to replace brake pads and shifter cables, also got cleaning and lubing stuff for chain.

Turns out, I have to change chain.
I think the chainring and cassette might need replacement too; although I’m not sure when should I change that. Shifting is really not smooth, had very rare chain drops but shifting took long times and hits hard.

Rear brake is fine, front one is a bit weak and loud but hopefully new pads will solve that.

My question is:
What parts should I get?
It’s a stock KTM Chicago 27,5 MTB.

Current set:
Chaingring: Shimano FC-M311 (3×8)
Cassette: Shimano CS-HG 31-8
Rear Derailleur: Shimano RD-M360

I’d like to replace them with parts that won’t brake the bank, enough for weekend hill climbing, but will last a bit. Located in EU, HU.

Thank you in advance for suggestions.

by Jaca666