yeah, my G51 is a cheap moto too and it can do HDR on the back but not the front.

HDR kinda requires multiple sensors to work in any reasonable situation doing selfies, so it can concurrrently capture multiple exposures.

even still, i did HDRs with my mother's Canon EOS with a tripod back in the day using multiple shot bracketed exposure setting. takes about 10 seconds in total. but the images are legit HDR after they get processed

most phone camera HDR range is narrow compared to what you can do with a pro camera