Respiratory tracking was just added to the FR245. Here's some proof. Mine updated to 3.90 last night and I noticed the Health Stats page had a new empty slot at the bottom. :
3x Soft Clear Protective Film Guard For Garmin Forerunner 245/245m Music Fr245 Watch Smartwatch Screen Protector Cover(not Glass - Smart Accessories - AliExpress
B New - G Fr 245 WHITE - GPS Rg Sh 010-02120-22 £83.64 thenationalherald.com
Garmin Forerunner 245 Music GPS Watch In-Depth Review | DC Rainmaker
Garmin Forerunner 245 Music GPS Watch In-Depth Review | DC Rainmaker