Your requirements don't really match with the parts you gave as example ... the Sanken part for example is an array of 4 Darlington , with a beta/hFe of 1000 and resistors built in.
An a "beginner dyi project" coupled with high voltage? You have people that don't mind working with high voltage but are picky about surface mount components?
You can get individual transistors in TO92 (through hole) packages for 10 cents in quantity, like MPSA42/43 , KSP42TA etc .. through they have kind of low gain but you said 50mA, so if you have to push 2-3 mA into the base it shouldn't be a big deal.
There's surface mount transistors with higher gains, like for example these ones with gain of 100
FCX458TA : 400v 0.225A SOT89-3
https://www.digikey.com/en/products/detail/diodes-incorporated/FCX458TA/260713The middle pin (collector) is connected to the tab on the other side, so if you want to make even more beginner friendly you could cut the middle pin short to make more spacing and make it easier to solder.
FFMT497TA : 300v 0.5A SOT23-3
https://www.digikey.com/en/products/detail/diodes-incorporated/FMMT497TA/92673Gain of around 80. You have to be blind to not be able to solder the pins with how much spacing you have. Could even bend the pins and make it through hole, but it's spacing of 2 mm-ish
FZT857 : 300v 3.5A sot223-3
https://www.digikey.com/en/products/detail/diodes-incorporated/FZT857TA/96593gain of 100 ... even bigger tab, same as above you could cut the middle pin to make more safe to solder for beginners, with around 4.5mm between the pins should be quite easy to solder to some big pads.