Too many stories of fuses being jumpered over and whatnot to trust a used meter for high power use unless you're willing and capable to open it up and verify it yourself.
Fluke seems like a good go-to as they've sort of made their name on stuff like this, but there was a thread discussing at least one Brymen meter in an industrial application and the guy using it seemed to be quite pleased overall, maybe worth a search. I've been quite happy with my Brymen too, but I don't deal with those voltages generally, so my usage case probably doesn't apply all that well to the OP's. I remember Dave did some comprehensive durability tests on some of the Keysight meters, they seemed like they held up well. Keysight currently has at least two meters rated IP67 and CAT III 1000V / CAT IV 600V.
Don't know if you've already considered it, but once you find a meter you consider up to your standards, maybe look at going with probes with a more comprehensive guard or better insulation rating too. A capable meter will probably come with good ones, but getting probes that are easy to use with all the safety precautions in place and that are comfortable and grippy in your hands may be slightly different than the ones supplied with the meter. Worth considering, maybe not necessarily required.