Help! Receiver or preamp? Im overwhelmed...

I need some help. Been gone for years and much has changed and Im just overwhelmed with the years of info on the forums. I dont want to make a foolish decision and would so appreciate the communities gracious knowledge and assistance.

Im 75% music and 25% HT. 

Paradigm Studio 100 v4 mains Paradigm CC690 center 
Paradigm V2monitor surrounds
SVS PB13 Ultra Sub
Emotiva XPA 5 amp (200x5)
Keeping all the above

The old 5 channel Rotel HT1055 receiver (no HDMI) needs to upgrade even though I love the sound! Im fine with 5.1 and not interested in Atmos. Im also fine with a used item. What do you reccomend for some killer sound and updated HDMI?

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.
Marantz is the best sound I’ve ever used.I bought them on eBay a year ago and they are still in perfect condition.
Seems like you like the Rotel sound. With music your main priority, Why spend the money on a video upgrade which may introduce a possible audio downgrade? You can get a 4K 4x1 HDMI switcher for about $300. It will have a 5.1 digital output to connect to the Rotel. Use rest of budget for bi wire or something.
You might find it interesting to disconnect your rears for a bit and use those channels to see how good the studio 100 would sound bi amped