Welcome to the community, Shelly! The “best” might be subjective, and like you said, there are not a ton of options, but two major brands to consider are Forest River and Coachmen. Each brand has a few pop-up camper models with bathrooms and I believe they all can be had for less than $25k new. You can learn more about the exact models here: https://camperfaqs.com/pop-up-campers-with-bathrooms
That only includes tent campers since you specifically mentioned that, not A-frames, or hard-sided popups, which some like to lump into the same category.
My in-laws have a Jayco jaysport with a toilet. They love it. Jayco stopped making pop-ups a few years back though, but you could probably find a decent deal on a used one. Also, when you say bathroom, do you mean shower and toilet or just toilet?
You might want to add Opus to your short list. They make pop-up tent campers for off-road use and have a portable toilet and a shower (with hot water) in a tent. So technically not a bathroom but will allow oyu to do your bathroom duties. I’m not about to down-size to a pop-up but if I did it would be an Opus.
Before we went full time we had a Coachmen v-trec v3. It had a cassette toilet and shower in the unit. I miss how easy it was to haul that thing around lol.