Yeah HRM training is very different, if it gets too high, slowing down or even walking might be necessary.
I also echo the distrust in wrist based HRM, you really want a proper HRM strap and they are pretty affordable compared to watches.
A Polar H9 for example is very high quality and easily less than US$80.
TIL where “Catch-22” comes from. Thanks, you really are a fine architect, importer and/or exporter, and latex manufacturer.