Making the irrigation system winter-proof - only a compressor?

Hello,
In our small garden, due to our low water pressure, I laid three separate PE pipe lines with pop-up sprinklers for rough watering. The first line ends after about 10m at a larger pop-up sprinkler (Gardena OS 140). The other two lines run via a small pop-up sprinkler (Gardena T100) to a total of about 8m, also ending at a larger pop-up sprinkler (Gardena OS 140), so two sprinklers are connected in each case.
All lines (PE pipes) are connected with a 1.5m long water hose, which in turn are connected to a 4-way distributor that is attached to the garden faucet (outdoor water tap). So I can easily detach each individual water hose and theoretically blow air through it.

Now I have heard that you have to winterize your irrigation system. For this reason, I installed a drainage valve about halfway on all three lines. However, since I have now read that these valves sometimes do not work or break quickly, I am wondering how I can be sure that no frost damage occurs to the PE pipes and the pop-up sprinklers during winter.

I read on the internet earlier that there apparently are people who empty such short lines with a bicycle pump, although it is unclear to me with which adapters this is done. Otherwise, compressors are of course widely used. If it can be avoided, I would not want to buy a compressor just for this. Others write that they never drain before winter.

I would therefore be interested in how you make your drainage systems winterproof (or not?) and whether you have also found ways and means to do this without a compressor.

Since my garden slopes slightly, I have also installed a drainage valve at the lowest point. It is accessible and can be unscrewed if necessary, allowing the remaining water to drain. If your garden is flat, I would build a small shaft. A small mash barrel, buried in the ground with the bottom cut out, is enough for this. At its lower part, you simply insert the irrigation pipe and install a small valve (ball valve or something similar). You just open it in winter so the water can drain.

Attach the compressor and let it run for a while. When it gets really cold, you'll be on the safe side.

I failed to drain the pipes last winter, but nothing happened. There are eight branched pop-up sprinklers and about 25 meters of drip hoses. I assume that since I usually stop automatic watering by the end of August, the water will be gone anyway by the frost at the end of October / beginning of November.

I wouldn't necessarily rely on that. The system should be sealed, so nothing should evaporate. There's also the question of how deep the ground frost penetrates in winter and whether it even reaches the pipes. The pipes usually tolerate a bit of frost, but I wouldn't want to take any chances.