From what I can see, youve attached them to the deck with a few screws on each side?? Likely an accident waiting to happen. You want to hang the stairs with the appropriate stringer bracket. You could also buy metal stringers from HD which can be bolted on through the frame of your deck. That might be the easiest diy option for you as it doesnt appear as though your stairs are a focal point. You just have to measure your height and purchase the corresponding stringers. You could also probably use your existing step decking boards to keep it as inexpensive as possible.
https://www.homedepot.ca/search?q=stringer#!q=stringer
1968 Impala: Status: Stored
1977 Dodge Triple E RV: Sold
1989 Mercedes Benz 420 SEL: Sold
2008 Mercedes Benz C230: Cruising
2000 Bluebird TC2000: Build phase of skoolie project
2018 Rav4 XLE: New baby friendly daily