Get metal shaker balls. They're 80% as good as a blender and 5% of the clean up work. (Also take out the rubbish plastic mesh mixer thing that huel put in their shaker cups.
12 Pcs Stainless Steel Bottle Mixer Ball Stainless Steel Mixing Balls Shaker Bottle Ball Replacement for Drink Bottle Cup
https://www.amazon.co.uk/dp/B07SC4CV1T/ref=cm_sw_r_apan_glt_fabc_NNVG7251XMV1N7HGGWJG
Off-brand ones would work, but also you can buy metal wire balls to go in bottles that very much do the job too
12 Pcs Stainless Steel Bottle Mixer Ball Stainless Steel Mixing Balls Shaker Bottle Ball Replacement for Drink Bottle Cup https://www.amazon.co.uk/dp/B07SC4CV1T/ref=cm_sw_r_cp_api_glt_fabc_Y5VFBG9JD85HAQ4GX5RB