I don’t have a laser, but I keep up on the laser topics on the forum, and I’ve been able to help several people get their laser working. I’ve seen several times where fan commands were initially used to get thing up and running, but long term, there was quality issues with the running the laser using a fan pin. They eventually made firmware changes so that inline laser commands can be used, and werer happy. That is an ‘S’ parameter of the G0/G1/G2/G3 commands is used to specify laser output.
The last time I checked, of the firmware that V1 maintains, only the Rambo boards and the SKR Pro boards had firmware with the inline laser enabled. If you elect to try and get inline laser commands running for your SKR 1.4 Turbo, I suggest you download the source for either the Rambo firmware or the SKR Pro firmware and run a ‘diff’ program using configuration.h and configuration_Adv.h between your source and source with lasers enabled. I don’t know how many are really necessary, but there were a fair number of changes (some of them not obvious), between V1 maintain firmware with and without laser support enabled when I ran this diff.
Lately I’ve been using Meld as my diff tool. The first post in this topic contains a test file with inline commands.