If it's any consolation OP I had both endoscopy and colonoscopy on the same day. The prep was ok, but my god it worked very fast for the first round! Took me two hours to get through it though.
I'm still laughing now, as I was to take the second round of prep at 6am, so I set alarms all over the shop but would you believe, I slept through the bloody alarms and woke at 8 am! I had visions of me pooping in the car on the way over.... I ran downstairs, made up the prep and chugged it down in about 40 minutes so I'd be off the throne in time 😊. That worked!
Anyway, on with the story..... I have a terror of anything going into my mouth (have sedation for the dentist), so I explained that the mouth guard was going to be an issue for the endoscopy. Honestly they were so brilliant about it, as I lay on the table they tried to insert it, but not happening, so doc said OK we'll do the sedation and then put it in, take some deep breaths there now, and folks, the next thing I knew I was in recovery.
They were checking for nasty stuff both ends, but thankfully all well apart from some inflammation in the oesophagus and a small polyp. You will be fine OP, best of luck.