Can I re-enter Thailand for another 90 days with a single-entry e-visa?

No

90days of validity of the visa to enter thailand and get stamp of 90days of stay when u enter...u can get a re entry permit for not losing that stamp when u go out of thailand but no extra days will be added when u come back to thailand again

Yes, you have 90 days to enter. Once you enter, you'll get a 60-day stay. You can extend in country for 30 days more.

No, you cannot purchase a re-entry permit and then come back for another 90 days.

The visa is single entry. Once you enter Thailand you will receive a 90-day entry stamp and then your visa is done. You no longer have a visa. The visa is what gives you 90 days on entry.

If you want to leave during your 90 days without losing your stamp, you can purchase a re-entry permit. All that does is mean your stamp isn't cancelled when you leave. The time is still ticking. If your entry stamp expires on August 1st and you leave on July 1st and return July 15th, you'll be stamped in until August 1st because you are re-entering on your existing stamp.