Just the Goods' hair care products have not been tested officially in a variety of scenarios with respect to colour treatment/processing (i.e. permanent, gloss, semi-permanent, wash in, henna, stripped before color (or not), etc). As such, it's not really possible to say one way or the other since what is safe for one person's circumstances may not be for someone else.
Clary sage is an ingredient found in some hair care products specifically designed for colour-treated hair, and yarrow is colloquially believed to reverse grey hair back to blonde (although there is no scientific evidence to support such a claim). Ultimately, it may be best to conduct a strand test to determine suitability.
Please ntoe: Just the Goods carries plastic-free hair care products by Jack59, including shampoo and conditioner designed specifically for processed blonde hair: https://justthegoods.net/search?q=blonde