Had a similar issue with my handmade jewelry shop last year, checkout would freeze randomly and I only realized how many sales I was losing after a customer emailed me. Turned out it was mostly UX problems. I got outside help after getting fed up and a friend nudged me. You could check Web Agency just to see how they structure things. It’s not instant fix, but smoothing the flow really helped in my case. Really glad I looked into it before things got worse.