What part of Europe are you in? Because it depends on the parts availability. Toyotas are fine, but at your budget, all the cars start suffering from old. Doesn't matter the brand. Based on your description of rust, I'm assuming it gets cold and wet where you are.

Edit: 160k km isn't a lot of distance done. That's like a 6 year old car where I'm from, but I'm assuming you live in a city and I'm assuming lots of people practice extended service intervals so it's a lot rougher on them.

03/MK4 Golfs have oddball plastics and have stuff fail like the headliner. Also radio codes (radio locks out if the battery is disconnected due to anti theft measures). If you do buy a golf or other VAG product, get a VW specific scan tool, like a rosstech hex v2 or an OBD-Eleven. Highly recommend, super helpful with maintanence. There's other specific scan tools for other vehicles, but VCDS (needs hexv2 and a laptop) lets you do a lot of neat stuff, and its probably the most indepth tool a user can buy outside of dealership level stuff out of most makes of cars. I don't think there's an equivalent for Toyota.

I have a VW Passat 2.5 (US specific model) and it's been pretty good at 260k kms. It has some quirks but it's not bad. That said the 2.5 07K (Second gen) is one of the more reliable engines VW made, right after the 1.9 TDI ALH. (Only way you can get this engine is buying a car imported from the US. They do exist but they're not super common and they're more expensive than the euro counterparts.

Basically, I divide issues into three groups. Vehicle is suffering from old Vehicle got damaged by user error Vehicle has a specific fault/quirk to that model of vehicle

Issues can usually be grouped into one of the three groups, sometimes it's a combination of both.

If an issue is in the first or third group, is it easily remediated and does it impact a vehicle inspection.

If it's in the second group, is there more damage than you think.

Edit 2: I forgot about displacement tax