I doubt there's anything on the market that will integrate volume control into the TV remote, as it would require HDMI CEC to do this.
If you use any smart apps or the internal tuner on the TV, then you cannot intercept the audio on the incoming HDMI, as this won't pick up the internal TV apps or tuner. This would require audio ARC - which is possible, but expensive.
Something like this has a volume control with remote.
Amazon product ASIN B087JJ24SG
Then just get yourself a decent programmable remote control - 1-for-all or similar and map the volume control to the remote code on the optical audio extractor.
Otherwise, quite a few TVs do still have a 3.5mm headphone output, so you could just get lucky and find one you like that has one!
Final option is to get an AV processor - preamp in other words, which will work correctly with the TV and have line level outputs for your powered speakers. At a push, you could just get a much cheaper integrated receiver and use the headphone output to drive your speakers.
Plenty of options, depending upon budget etc.