I’ve had one CNN of these over two years now for my system. Works fine. Have similar smaller units for computers in two rooms, a larger one for TV/audio in another room. Output is clean, to keep rfi/emi off input I use simple clamp-on ferrite chokes - works for my ham radio equipment.
you did specify inexpensive.
APC UPS 1500VA Sine Wave UPS Battery Backup, BR1500MS2 Backup Battery Power Supply with AVR, (2) USB Charger Ports https://www.amazon.com/dp/B08GRY1W93/ref=cm_sw_r_cp_api_i_DT698HR0MVRKADDH5ASB?_encoding=UTF8&psc=1