This is a remix from https://www.thingiverse.com/thing:3351902 with flat style numbers so that you are able to print them without supports and raft/brim. This is very important to make them fit into the rings. Even without rafts etc, it is very tricky.

But I found a nice and easy solution to make the numbers fit easily. Hold the ring with the number you want to handle showing to the top right - 2:00 o'clock, place the number on it, so that it would almost fit the hole.

Then use a regular lighter (see attached photo) with a rounded body, hold the flame with 2cm distance for 1-2 seconds next to the number and then use the round part of the lighter to push it into the hole and roll it from left to right, so that all parts of the number will be pressed into and are flat.

Make sure to not heat it for too long, else it will melt or stick to the lighter or so.
Also make sure to not use your thumb or any other finger to press them into, because it will end up with your finger prints melted into the numbers or that something looks bad.

Best is to print one garbage ring and some numbers to get some practice. Once your made it through the first complete ring (for practice), every other ring will be done completely within less than 5 minutes.

And it looks way better than just keep it with the number holes :)

One addition: To assemble everything together, you should use this stronger clip instead the original one, because it is much much easier to push it into (hard enough at all)
https://www.thingiverse.com/thing:3625865

Anycubic

All-metal Mega

No

No

0.2

10%

I printed them with 190°C and 50°C bed, worked perfectly