Health boost effects don't stack. The armor would be useless near a beacon or vice versa. The player won't be able to use a health boost potion too. The best choice is to modify the attributes. If you don't want to use commands, you can use DTM's Toolkit - Attributes plugin for mcreator.
/attribute @s minecraft:generic.max_health base set 40
https://ibb.co/RGFwsdq
dont use commands, not always recommended
Make it health boost along with instant health
Health boost effects don't stack. The armor would be useless near a beacon or vice versa. The player won't be able to use a health boost potion too. The best choice is to modify the attributes. If you don't want to use commands, you can use DTM's Toolkit - Attributes plugin for mcreator.