What if you want to build a phone handset that you don't want to support forever? It has to be online but there is no realistic way the original hardware will s

What if you want to build a phone handset that you don't want to support forever? It has to be online but there is no realistic way the original hardware will support continuous upgrades, even my Samsung S8, which is hardly ancient, is already slow (for reasons unknown) and will not survive very long.