Earlier this year, I went to a concert that required the Ticketmaster app. I searched desperately for an option to print off a paper ticket, but didn't find one. I enabled the Google Play features in GrapheneOS to install it, and I hated the Ticketmaster app experience the entire time. (Concert was great though)
P.S. Stop sideloading apps. Don't use Big Tech vocabulary for something that we did before. You installed the app, regardless of how you did it.
FWIW you can just about always pick them up will-call.
Ticketmaster will tell you this is impossible, but the venue always has a way around it, for in case you lose/drop your phone, etc.
And it helps reinforce to the venue that ticketmaster is not perfect.
P.S. Stop sideloading apps. Don't use Big Tech vocabulary for something that we did before. You installed the app, regardless of how you did it.