There is loss in everything.
A dipole with coax feed has a loss in the coax (dielectric loss). This is given in charts. There is also loss due to SWR miss match. But there is a lot of cheap, substandard Chinese coax on sale so to be sure you should measure it.
An endfed matching unit will have loss. A lot of authors on here have to done a lot of work to try to reduce those losses. The loss you will achieve when you make a matching unit depends on the components matching what the author used and the quality of construction.
Either way there will be some loss. The aim is to get the matching unit loss to be no more than the equivalent coax loss and hopefully better.
I use RG174 for coax fed dipoles. IMHO it’s OK for use up to 14MHz and at 18MHz it is starting to get too lossy in the 10m length I use. My 12/10m 1/4wave and 10m delta loop use about 4m of RG58 to help keep the losses down. I would not want to carry 10m of RG58 with me!
Which is best? Which has lowest loss? It depends. So build an EFHW and link dipole and compare them. They don’t cost much to make and there is lots of fun to be had building and experimenting.