As long as you are in the Dev Channel you can install updates that don't expire for a while. All Dev Channel updates prior to build 22468 expire at the end of this month, the current build 22471 won't expire until September 2022. By the time the current build will expire there'll be newer builds you can install. Changing from the Dev Channel to the Beta Channel is unfortunately only an option in the rare cases when both have the same build. To move to the Beta or Release Preview channel now would require a clean install, which isn't possible because MS only provides a VHDX with a Dev Channel build for download.