In the shot term, a clutched rear derailleur could help and they’re relatively cheap.

On the new bike front, firstly I’d say get out and ride them if you can and compare the bang for buck equipment levels. I don’t think there’s much between the Chameleon and the Honzo. The Marin is full sus and so you’re losing out on bits to get that extra suspension in the rear. You need to weigh up if the rear suspension is worth the trade off. If you like the full suspensionthen you could be better off looking for something higher spec and used to maximise the benefit to fit in your budget