The set of radials will improve the antenna.
Sometime it helps to connect any metalic parts available in the field to the radial system, e.g. the upper metalic bit of the wall.
I remember playing with a FT817 and a “miracle whip” antenna during a peak of a sun cycle and making many SSB contacts >1500 km… and this was indoor. No set of radials was used… BUT all the contacted stations had huge antennas.
Would be interesting to see to which extent digital modes like FT8 or JT9 can compensate a bad antenna…
With wisper it will compensate! Used QCX minis and a 80cm (2,6’) vertical mobile antenna for different bands 40m, 30m, 20m and was received worldwide, e.g. ZL, VK, Antarctica, etc.