Let's sort some things related your post based on facts.
- Multiple entry is not available for Non-O for any reason through eVisa application
- Non-OA visa is available in your country only (not inside Thailand) and for being over 50 years old
- No RTE/RTCG around Thailand issues multiple entry Non-O based on retirement
- No more "in-person" RTE/RTCG in Southeast Asia as of 1 Jan 2025 (edited)
- You can apply for single entry Non-O based on retirement inside Thailand (by having 800K baht in a Thai bank account) or outside Thailand. Then following 1-year extension for the same reason in Thailand and a re-entry permit
- You cannot apply for Non-O visa based on spouse to a Thai without legal marriage
We are not going to speculate wild options.
@Andrew ****
, Please consider these facts, sort your idea, and make a new posts.