Ok, here’s the final setup. To summarize I have an extension cord plugged into the outlet, then 3 items plugged into the extension cord (Roomba, Litter Box, and Power Strip), then I have the small air purifier plugged into the power strip.
The following 3 items are plugged into the extension cord
Roomba https://www.amazon.com/dp/B08C4LC7TG/ref=cm_sw_r_cp_api_glt_i_FBSHNTC1G8GQRYYH7CXK
Litter Box https://www.amazon.com/dp/B08T9CCP1M/ref=cm_sw_r_awdo_H46AT3HMTWVDNHYYGRK2
Power Strip GE Pro 3-Outlet Power Strip with Surge Protection, 8 Ft Designer Braided Extension Cord, Grounded, Flat Plug, 250 Joules, Warranty, UL Listed, Gray/White, 38433 https://www.amazon.com/dp/B073R2D51S/ref=cm_sw_r_cp_api_glt_i_KZN6835FZW78ARHD4H1W?_encoding=UTF8&psc=1
And finally, the small air purifier is plugged into power strip, attached to side of litter box with double sided tape
Air Purifier https://www.amazon.com/dp/B00OLBR0H0/ref=cm_sw_r_cp_api_glt_i_0DY9P06TB62EJBM751DX?_encoding=UTF8&psc=1