What can be read from the visualization of your bed geometry is that the left side (when facing the printer) of the X-axis is lower than the right side, so your plate is tilted.
If what I understood so far about ABL is correct, when printing with a uneven bed surface, the Z height will be adjusted according the probed data.
Yes, true (see Automatic Bed Leveling (ABL) with a sensor (BLTouch, inductive, capacitive), how does it work?), but that is a sales pitch, you don't want the bottom of every print to be skew! A probe is not meant for those skew plates it should be used for local dips and dents in the build plate. ABL (or UBL, see What is ABL or UBL? Is this the same?) will scan the geometry of the build plate, but you still need to supply a bed as level as possible. With the bed geometry results from the question, you need to level better! You should either shim the left side standoffs so that the bed is more level. A probe shouldn't have to compensate for the a skew plate, it can, but it should not. It is either wrongly trammed, or there is a hardware problem that is commonly found on these printers (X gantry is not parallel to the bed and has play, due to the cheap roller system and simple single driven lead screw design). This is described below (to make a more complete answer) so that other readers that run into similar issues can use this information
A possible alternative is that Looks like there is something wrong with your X-gantry, make sure the X-gantry is parallel to the bed, e.g. as seen in the following image:
This could be a result of lack of maintenance, considering the printer is from 2018, the frame needs to be checked. At the moment, the right side is closer (high X values), so either your bed is higher on the right side, but more likely (as you use fixed length stand-off's) the X gantry is tilting down on the right side (when facing the printer) and therefore reporting closer to the bed as if the bed is higher to the right, e.g. see adapted schematic:
This is a very common problem with the Ender 3 type, especially the single lead screw driven designs. To fix this permanently, installing a second lead screw is advised. As a quick fix, you need to inspect the complete roller system on both Z-axis posts and retighten them.
An excellent example of the problems with the X-gantry is shown in this video:
This video is a very good example for the problems with the portal style printers that use rollers for guiding the gantry. Look at the play in the (X-Z) gantry, this would cause the exact same bed visualization as posted in the question (note that the video is centered on the installation and software changes, but the printer used has seen better days and should have been maintained prior to installing bed leveling).
