The Speaker of the House does not have term limit. It may not be bad idea if Trump serve American as the Speaker of the House because he can work for 10+ more years.
Whereas as President, he can only work for one more term and he will also face a lot of challenge from the congress.
Besides, Trump has already completed the mission to overthrow the Satanic Cabal. The next step is to rebuild America so that the Speaker of the House of Representatives has better influence over domestic policy.