Hi there. I had my first time 12ml of Juvederm Voluma at Androfill UK in August 2022.
I'm circumcised and my starting stats were:
BPEL - 6.75
EG - 4.75
After:
EG - 5.5" near base tapering to 5.1 by the glans. I consider this a good result compared to others experience on here. 6 months on I've lost very little if at all which is surprising but I am a little older so metabolism is slower which prob helps.
To your questions...
1. Erection firmness - short answer is yes, it's less firm. Different people have a different starting firmness which I think explains the variance in reports. For me, I'm naturally skinny and had slim shaft without much fat and so a fairly firm erection. So it makes sense that adding the less firm filler around this will "pad" it a bit and this took some getting used to at first. I would say, contrary to the clinics own "filler firmness" table, that Juvederm is about 60 to 70% max of my previous shaft firmness. I'm as good as married but I don't think it would be enough for any new partner to notice. However my partners first words (3 weeks after op) were "it feels squishy" which was kinda disappointing as the overall aesthetic result, esp when flaccid is great. I found the filler was still "settling in" the 4 to 8 week period after. It seems to bond better with the surrounding tissue which reduced the squishiness observed in the first month. I also found I can get back to say 90% of my old firmness by simply using a cock ring and or a half dose of viagra.
The first 24 hours for molding are absolutely key. Tip - highly recommend some viagra for back up. Normally I have zero probs getting hard but I found holding an erection in the 48 hrs post op unexpectedly difficult which meant shaping to the profile I wanted was challenging.
2. Pumping - I don't do any of this PE stuff as dont have the time so can't answer this one, sorry!
3. Ellanse - to be honest...If I could start again I'd probably go straight to trying Ellanse but I can understand why the clinic is wary. Much harder to sort out issues if it has a bad result. I think I will try this in 2 to 3 years time depending on how the market evolves but now I have to wait for the HA to dissipate.
4. Does sex feel different? Yes and no. My advice would be give yourself a few months to get used to it. Contrary to what clinics like to say, my shaft is slightly less sensitive now but the glans are same as before. For the first few months I could go for ages and sometimes took a long time to finish.
Androfill tend to inject slightly above the base, in the lower two thirds of the shaft which creates a slight bulb /butt plug type profile. And the first time we had sex there some weird noises happening

This settled down as the shape settled.
Masturbation is also different. Before I had a good "approach" with my hand to my wider glans from a slimmer shaft. Post HA I've had to change my technique. A few months on and it's almost back to prev sensation.
My wife? I'm not sure she feels much of a difference. I can feel her a bit more I guess but not by that much. I'm lucky in that she usually has 2-3 orgasms quite quickly from PIV. Post HA it's pretty much the same! She's had a few girthier (5.75 + ??) guys before me and said it was fun but she still seems to get off on my cock at EG 4.75 as much as the new 5.5" girth. She thought I was a bit mad to get it done and wasnt overly impressed tbh. For the first few months I think she might have preferred my firmer but much slimmer pre op dick. One diff I have noticed is that with a small butt plug her pussy is much tighter now. I think she could take more girth fairly easily...perhaps 6" + EG and I have bought a dildo with 6 25" to experiment with her soon. But..y'know...the old stuff holds true. Think we men are waaaay to preoccupied with size. Just focussing on all the other stuff, making her comfortable, foreplay with hands, mouth, makes just as much of a diff to her ability to climax hard.
Hope this helps and good luck.