Would OTPing Rengar Be Viable In Low Elo?

Before I start, yes I know the common wisdom is to not play any high skill champions in low elo, but I'm sure many people have gone through this as well.

So for context, I used to play back in S9. Played mainly Eve & Rengar jungle. Peaked Plat 4.

After that, I took a +5 year break & just recently started playing again (2 weeks ago).

I'm obviously rusty with mechanics and there is a lot of stuff to learn. Thats why I've been just spamming Amumu jungle. Currently in Silver 3. 50-55% winrate.

I know that to learn jungle & the game again, it would make most sense to just keep playing Amumu. Simple champ, focus on macro, tempo, ganks etc. but the problem is that Amumu is extremely boring.

I've always enjoyed playing high skill ceiling champs & trying to master them. Super rewarding.

I saw that Rengar is at a pretty bad spot in terms of winrate so my question is:

Do you think it makes sense to stick to Amumu for 100-200 games to learn fundamentals or is it fine to pick up a more complex champion to focus on learning?

How big of a disadvantage it would be?

And since Rengar is fairly weak right now, is there some other champs I should look at that are super rewarding to master overtime?

I know, a bit of a hard question to answer but would appreciate any thoughts, experiences or opinions you have! Thank you.