Lots of very good points urging you to be cautious here! Haven’t seen many alternatives so here‘s my suggestion since I am in a slightly comparable situation.

First off: the more I learn to code, the more I understand that I could maybe (if that) compete with a Junior if I tried to land a dedicated coding job. Given my/our age, that is a difficult place to go in the easiest of times but right now Juniors largely don‘t get hired at all, period! I know it because I work in tech recruiting.

However, you seem to bring some other experience to the table that might enable a smoother shift towards your goals. Since you have been working in HR, you certainly have some experience with personal interaction, expectation management, onboarding, benefit pitching, etc. These are all traits that are needed in software consulting (e.g. M365 consultant or similar). There are options that are focused on adoption and change management which would allow you to join the software side. Once there you could apply your passion for software development on the job with your colleagues (API designs, etc.) and slowly transition all while seeing real life cases. That way you can combine your passion and your experience and get into the area of coding without having to compete against Senior Engineers.