If you are going to get a radio with a built in ATU, then you should consider a Windom antenna. Windoms also one of the most common and practical types of antenna. With a little ingenuity, they can even be connected at the end, just like an EFHW, which means there is no (potentially lossy) coax to carry. As you will see in this post, they are also ideal as a first time antenna project:
The lightest version I have made so far weighs 184 grams (including the spool) which, whilst not the lightest SOTA antenna in the world, is pretty good for a Windom. The more reasonable feedpoint impedance of 200 - 300 Ohms also means potentially lower losses than random wires with 9:1 baluns and some other >1:50 impedance transformers; although other factors will also affect losses. Whatever you decide, I’m glad to hear you’re building your own. It’s much more fun than buying ready made antennas.
73 de OE6FEG
Matt