2019 Prius Slow Coolant Leak

No. It might cost a little mpg. Toyota design it to open on high exhaust pressure alone when high rpms are being used.

There is no single root cause of gen3 head gasket failures unless you want to blame the engine design and testing team when it was adapted from a Corolla for use in a hybrid. It worked fine in a conventional Corolla which even had the egr system. The Corolla also had low tension rings which lead to excessive oil burning as did Camry and Rav4s but Corollas did not blow head gaskets without overheating.

It's clear Toyota quickly knew they had problems using the Corolla engine in a thermal cycling hybrid with an Atkinson cycle camshaft. Five years later a redesigned 1.8L solved the hg problems for gen4 which is why many have embraced using parts of a gen4 in a gen3 car, eg a Frankengine. Hybrid Pit now sells a rebuilt gen4 block, a modified head gasket and a gen3 head topped with a gen4 cam carrier. But most older gen3s are not worth using their most expensive option when fully rebuilt and moderately improved gen3 engines are available for less.