I twisted a pair of Aluminium (6061 😉 ) Scott riser bars about 14 years ago which I used on my trials bike.
These were pretty low budget xc bars which came off my second hand Klein xc bike I’d bought previously. It took a few years of drop offs, gap jumps and repeated throwing the bike to the ground as I fell off stuff before they twisted. It’s a miracle they survived that long.
My crowning achievement was a 7ft drop off the sea wall onto the flat pavement below. Obviously landed rear wheel first but I remember the front wheel coming down with an almighty thwack afterwards. IIRC I was sporting some equally cheap FSA riser bars by this point and some unforgiving Kona P2 steel forks.
I wouldn’t be too worried about one failing from just riding around. If you are worried about fatigue then there are plenty of cheap options in CRC sales for something new.