I unfortunately cannot answer the Bluetooth connection performance question on the R3, as they haven't shipped yet. Only a few people have received the R3 for early reviews and I am not one of them.
Here are the 2 reviews from Headfonics and Headfonia (You might want to send these two reviewers your question, as they will have have a good idea how well it works)
https://headfonics.com/2018/03/hiby-music-r3-review/
https://www.headfonia.com/review-hiby-audio-r3/
Hawaiian Bad Boy on this forum would probably know as well. His full review on the R3 should be coming soon:
Here's his original preview of the R3 in case you haven't seen it:
As far as whether or not you should keep the Q5 or not all depends on how you would use it. You mentioned that you would rather not stack items. If that is the case the Hiby R3 has the advantage over the Q5 as it is in all in one DAP player vs. just a DAC/Amp combo that requires another transport device. The R3 is about as portable as it gets for a music player. The portability/form factor and amazing touchscreen is the reason a lot of people here are excited about the R3. Just look at the great pictures on this thread that Hawaiian Bad Boy has posted.
If you plan to use efficient/easy to drive IEMs and headphones with the R3 then an external Amp/DAC isn't required. The quality of the DACs between the R3 and Q5 are going to be close. Although the Q5 does have dual DAC chips vs a single chip in the R3. However, both use high quality DAC implementations so I think you'll be pleased with the sound quality of both. The amp stage isn't going to be as powerful or flexible on the R3 as it is on the Q5, but it sounds like that isn't a main issue for you if you mainly are going to be driving the Pinnacle P1s with it. Are you planning on getting a balanced MMCX cable with a 2.5mm trrs jack for your P1s to use with the balanced port on the R3? I would recommend one as this would give you the most power out of the R3 to power them as they are 50ohms impedance. By no means inefficient but they will benefit from having some power on tap to crank them up!
There are a lot of aftermarket balanced MMCX cables terminated with a 2.5mm trrs jack that you can find on ebay, AliExpress, and Amazon.
Given the reception of their original R6 product I would expect the R3 to be top notch as well. Having their R6 model raise over $368k on Indigogo and now their R3 product at almost $280k doesn't just happen by accident. Hiby really listens to their customers and tries to make the best product they can. They also do a great job updating their firmware and adding new features to their DAP players after they are sold. I would expect Hiby's Bluetooth functionality to be flawless. It looks like Hiby is possibly working on getting Sony's LDAC wireless technology certified on the R3, but they are not able to currently discuss/guarantee this feature at this time. However, having LDAC support would make it a top notch Bluetooth streaming device, as many people regard this as the superior streaming codec for bluetooth. As I mentioned earlier there are a few reviewers on this forum that could answer your question on the current quality of the Bluetooth streaming on the R3.
You also mention that you use Spotify. If Hiby is able to get certified by Spotify and create a Spotify app similar to what they are doing with Tidal then that would be the icing on the cake for you. Even if the built in Spotify app doesn't happen it still gives you ability to use Bluetooth to stream songs from Spotify directly from your smartphone to the R3.
For $189, this device is a non-brainer for music enthusiasts. You will have to add the cost of a microSD card if you don't have one, but that's a requirement for almost every DAP player on the market. Even if you still have to buy a MicroSD card it's still a great value. I call it the little Swiss Army knife of DAPs.
Good luck in your decision.
