Yes last time I spent the summer in Pattaya 2019, I bought a Thai mobile 4G card & I was very impressed with the internet speed, often up to 30MB depending on where I was. Plus it was great value too. This allowed me to use VOIP & Skype Out well.
I might be lucky and find a condo with its own private internet, like True the comes via the TV. That would really help.
The nature of my work, I often have up to 20 tabs open in the internet browser & the VOIP going, so I certainly need strong steady internet.
Yes the coffee shops are an option, though I find I get distracted easily or if there's a lot of noise around it's hard to focus.
I'll email the Bali High office place, though looks like it only operates 9 - 5pm whilst I need 3 - 11pm most week days. I'd guess a lot of those co-working places on the list have gone out of business over the last year. I'm coming in June, so maybe a few options will appear for me before then.