Consider "Honey Teak" ... Expensive, has high learning curve, has the gloss and clear luster of varnish ..... but LASTS for 10-12 years (with minimum 'clear coating').
Signature Finish and Honey Teak Products - Honey Teak
Im a reformed varnish-aholic and have a "teakey". I'd rather go sailing than being a slave to 'varnish'.
Honey Teak comes 'closest' to a prime varnish job. Since its an acrylic-urethane 2-part catalyzed ... it can be put on wet-on-wet, can be flat sanded + buffed or hand-rubbed to a 'museum grade' finish.
To make Honey Teak and other 'modern' coating systems last, put them on THICK, maybe 50% thicker than the mfgrs. 'recommendations'. The 'moderns' have adequate UV filters (ferrous oxide) that protect the surface wood cells from UV destruction ... thicker is better.