It all depends on the key queries that promote your website, as well as the number of competitors in your niche.
Based on my experience, I can say that it has become a little more difficult now. A 301 redirect will not save you. It is only possible to quickly regain your position after changing URL addresses if your website is scanned quickly.
Imagine a situation where you decide to change your domain. How quickly will your positions recover? It will be similar with each of your URLs. Search robots will have to take several steps to redefine the positions for the new URLs. Your URLs were ranked based on certain factors. Google will recalculate these factors by going through each page involved in the ranking of a separate page, recalculating the link mass, determining relevance, and so on.
If, for example, you rank only the main page for certain keywords and you only need the rest to strengthen the position of the main page, feel free to change it. The main page of the site will drop for a short period (2-4 weeks), but later it will recover and is more likely to improve its ranking.
At least that's how it works for me. I've done this on seven websites, and the result is the same.