In the UK at least only 5000 representative households have their TVs monitored. All viewing figures are extrapolated from that. So not watching the race won’t impact the figures at all unless you have a recording device (you would know about this if you had it).
Giving the impression of a boycott is a separate thing, which maybe could work- making promoters, sponsors etc. think that you and loads of people will turn off. Of course in that case it doesn’t matter if you do watch it or not in the end, as nobody actually knows either way.
Whether things are the same in other countries I do not know.