A modern escort carrier would be austere and mission-specific

Would a modern escort carrier be a helicopter carrier like French or Spanish ships?

No. It would be closer to an austere logistics or Bay-class-style hull with a flat deck for limited carrier or ASW helicopter work.

Modern French or Spanish light carriers differ from true escort carriers. A closer analogy is a logistic-support or landing-platform-dock hull built to less demanding standards and fitted with a full flight deck. Such a ship could support helicopters, unmanned systems, or limited carrier tasks. Its purpose would be austere aviation support rather than service as a front-line fleet carrier.