As far as fearing pain: I got drugged up enough as I assume most did that you can’t feel a whole lot—& we aren’t talking anything beyond local anesthesia + strong paracetamol (just make sure you take something before bed or GG sleep). I will never get used to getting needles in gums tho.
If possible, seriously try to get a one-shot appointment. Mine had 5 1-hour visits every 2 weeks (not what I expected or would have signed up for) & each time they would spend like 15–20 minutes of that clearing out & reapplying a temporary resin. In this state your tooth is quite compromised state. My tooth ended up getting a fissure all along it after the penultimate visit—which ended up being irrepairable. Which meant they had to do an entire extraction for an implant wasting more money & time. I do not wish this on anyone.
Adding fuel to the shit fire was after visit 3 I had massive pain on the other side. They were going to start a root canal on that one too but I begged for a temporary filling (was supposed to hold up 2 months but has been a year) so I could still eat. Tooth 18 was under repair so I had moved all chewing to 31 as my mouth favors putting a majority of pressure on these 2 molars. I don’t think I could have reasonable eaten anything enjoyable for months if both sides were out.
Of note: the root canal isn’t like a finalized thing either. They seem to inevitably, eventually break down & will likely require an implant anyways in a few years. When my right side goes out—which it is—I may just consider doing another implant there too since it can be done in just 2 visits here.