Help! Receiver or preamp? Im overwhelmed...

Some great responses. I’m watching with interest because I am going through pretty much the exact same ordeal but with different equipment.
I’m leaning towards Anthem Pre/Pro to go along with my Aragon amps.
There are some used Anthem products online if you hunt around. A lot of audio dealers sell products on eBay. Now that Anthem brought out new models I’ve been looking for a used AVM 60. The AVM 50’s are nice units also and closer to your price range. I probably wouldn’t go any older than that though.
Good luck!

Compare Anthem with Marantz, et. Al...

for me, room correction is very important.  I am not sure where Marantz, Denon, Rotel are with RC.  I would compare Anthem with Yamaha, and I already stated why I had a preference for Anthem

Hello jsbranham7!  I'm in just your situation, HT and surround sound music, hooray! I recommend the Emotiva MC-700 preamp/control center. It offers first class sound, but fewer decoding choices than a surround sound receiver. A used near top or top of the line Integra receiver can be had for less than $300 (likely $200 or less) and offers ten or more decoding choices (lots of fun) plus radio and the sound is B to B+ (quite good). You can always put it in another room if you upgrade to one of the very pricy Pre-Pros.  Use the "preamp outs" on the Integra receiver. I have three such setups running in my home. The Emotiva MC-700 controls the main system. There are five systems in all, one using the receiver as its maker intended.

As sort of mentioned, I would post this question on a HT forum, not here...this is predominantly a 2 channel forum, although some here still introduce a sub to a 2 channel set up, ugh...🙄
If speakers are not doing it for you in the bass dept, time for a better "pair" of speakers.

Hello, I haven’t experience to advise you, but I have read one interesting article about Preamp vs Receiver – Detailed Comparison.