I wouldn’t say it’s a terrible text as it’s good to find out whether she would be up for non-alcoholic drinks. It could have been improved by adding some humour before asking tho

Wait a couple days and follow up with “don’t worry it’s not a trick question”

Move forward. "How's your insert day going"

Just looking at this screenshot she's right, it did come a bit out of nowhere.

"Gocha. We can take things slower ;)" or something along those lines

I definitely do sometimes but not usually. In this case the conversation was flowing and progressing well so I feel switching platforms would have interrupted that with little to no gain.

If a girl is bad at responding or if i can't meet her for a while then I'll switch

More of a general question than for a specific convo.

3am messages saying stuff like "hey you up" "im feeling spontaneous" "wyddd" etc

Probably need to get her investing again. Tell her how your weeks been and some fun stuff you've done, acting like she had asked. Work things out from there

She never acknowledged your plan for 8 that night, probably missed it in the message. When you next mention it she said she already has plans - probably legitimate. Using a takeaway there was not the right call, you should have just rescheduled.

Say something like "I misunderstood. Good, I like a confident girl" and fill in the rest

On bumble, not paid

Whatever you do don't fuck a pick up at the gym or everyone will know you as a creep.

She probably feels awkward for ghosting you and still seeing you, so you need to show (not tell) that there's nothing awkward.

If you make eye contact, just smile and nod. Next time do the same add a "hi". Next time add a "how are you?" Next time have a brief convo etc

No need to mention you remember her from Bumble

Screenshots?
"Are you always this difficult to make plans with?"