My experience starting with Spanish, and then trying French was that it still warded off most of the difficulty others in my class had.

There were loose patterns for grammatical gender for others to follow, but it mirrored Spanish well enough that it was ignorable. The next big thing that tripped classmates up was the subjunctive. French didn’t seem to use it as often, but the concepts largely translated.

There were a few false friends, but it seemed rare. Hearing spelling may be harder in French, there are a lot of homophones or near homophones.

All that to say, French should still largely be a quick win (in as much a language ever can be).