It is a mistake to under estimate the quality of the L1800. It's lineage goes back through the 1500w/1430 Artisan/1400/1390 - probably further. It has been the 'go to' mainstay of the small format (non sawgrass) sublimation industry for well over a decade It is a very good 'pro-sumar' photo printer.
The F100 is likely to be based on an home/office printer. The F500 is based on the SC-T3100 series with some eco tanks and some sublimation drivers (and an extra £1k) stuck on the side. it is a good printer, but it is only based on a plotter/plan printer, not a photo printer.
Inktec Sublinova is very good ink.
Not that any of that helps you with your situation.