Couple things to mention (note: I am not an expert at SEO. If you need exact answers or help reaching out to an SEO agency/specialist may be your best bet) :
Changing your software will more than likely itself cause a URL change as most software have some varying URL configurations/naming conventions. In addition, you changed the location of the software on your domain so this will also cause a URL change. During this period, your organic traffic may dip but should recover as the search engine re-indexes these new URLs.
301 means a permanent redirect and instructs the search engine the old URL should not be indexed anymore. A 301 passes all the link value a discarded URL has accumulated over the years over to the new URL, so it causes the new URL to gain or retain value. Thus, it is OK and recommended to leave these in place. More on redirects: https://yoast.com/which-redirect/
Meta keywords are no longer part of Google's and other search engine's algorithm.
Google in May did a huge algorithm change: https://medium.com/better-marketing/google-may-2020-algorithm-update-4-key-changes-and-how-to-adjust-9fdd6294b83c