It might be worth abandoning the modification of that extension cord and get a official surge protected extension cord, which these days doesn't cost too much and is significantly safer than the self modified one, which may cause serious problems or even dangerous situations.
I was using stuff like https://www.amazon.com/dp/B08P5LRY37 you can then remove the plug and put on a swedish one e.g. https://www.clasohlson.com/se/Jordad-stickpropp/p/22-1887
For the UK stuff which is the same voltage it works pretty well. For US stuff as the voltage difference is a problem.
You do need to be careful of the total amps as well but from what you listed the total power should be fine.
MOst of what you wrote should work fine on 230v I think, but double check.
For some things you can just replace the power cord. Looks like AppleTV supports 230v, and has a standard connector e.g. https://discussions.apple.com/thread/8522676 So something like https://www.clasohlson.com/se/Apparatsladd-C7,-1,8-m/p/22-457 might be good.