The switchbox I use is strictly if one has a power amplifier and want to use multiple sources. This has one RCA out and 4 RCA in's.
A IA with HT bypass is the best way to go, if you want best of the both worlds.
I was in a similar search, had eyes on Audiolab 6000A for quite sometime, but did not want to spend so much.
Can name a few:
Power amp preferred.
Your AVR should have Pre outs,
Need a IA with pre outs, without HTbypass will do. But Pre Out is must
Needs a pre amp to run a power amp, phone works too but pre amp sounds beautiful.
Here is the link of the switchbox:
https://amzn.to/3qCBZml
@SiR you can try this, get a AVR with Pre Outs for now with 2 speakers and a subwoofer if possible.
Enjoy it few months, then from the pre owned market get a used IA.
Hook up the IA to your existing speakers, add a good source and listen the difference.
If you like IA, you know what can better IA's do now. If you don't, you haven't broken your bank, a pre owned IA can come under 20k too.
I started my journey with AVR's too, bought a IA later just to see how it sounds on my system. That too was given to me by a friend a NAD320BEE which was more than 10-12 yrs old. But it blew me away, not that my Denon x3700 is bad but I love the pure sound a 2ch throws out. Since then 90% of my listening is on IA's or separates and not AVR.
This not may be the case with you, you may like the AVR more than IA. But you will accomplish 2 things:
1) Not spend unnecessary in one go, spend wisely over a period of time slowly.
2) The journey of changes these gadgets will bring to your system.
Point number two is the important one, the learning curve of the journey to get
best sound in your room. This is a never ending loop, but you will learn a lot and enjoy the journey. What pleases you matters most and not our opinions