Thank you so much for your help, I've got my coins back! You deserve the status 'hero member' !

I'll show here what I've done: it's a bit duplicate data from the links you've sent, but as I didn't find the pages you showed, maybe another person will find this post easier to find too.

So I thought I had an old(er) version of Electrum-XVG, but it turned out to be the latest version of this wallet. However, as I've seen on numerous posts, this one can't be connected to any server so it's a sort of worthless.
And when you start looking for newer versions, you end up with a bitcoin wallet with the same name.

So what to do if you have the Electrum-XVG wallet which can't connect to a server (the steps which worked for me)?

1. From within electrum-xvg go to the console and type listaddresses()
This will list all of your addresses, so you can check online (vergeexplorer.com) if there are any XVG coins on the addresses. I had done one transaction in 2017, and found it on the first address.

2. Then give the command dumpprivkeys()
It will dump all your private keys, which off course should be kept private

3. Then install Coinomi. I used the windows version.

4. Then create a new wallet and choose to store XVG in it.

5. Then from your wallet, choose 'sweep'. I'm not exactly sure how it works, but it 'takes over' from your old wallet. Coinomi support says at this moment "When you're sweeping a wallet by entering the private key a transaction is created which empties the source wallet (the wallet the key was exported from) and sends all funds to the destination wallet (the wallet the key was swept into, in this case, your Coinomi wallet). The funds are visible and accessible only from the destination wallet."

6. Then enter the first of your private keys. For me that was enough, after less than a minute I saw my XVG's in coinomi. I am not sure what to do if this shows no coins or only a part of them.

In 2017 I had an electrum wallet (2.4.1) for my XVG coins (Called Electrum-XVG). When I run it now, it doesn't seem to connect to any server (found multiple server addresses on various forums, but none of them worked): all I get is a red dot. When I install the latest version of electrum (via 'official site' in Electrum, it then redirects to vergecurrency.com), it doesn't re-create my old wallet with my seed phrase AND it seems it only works for bitcoins now? I run it on a different computer now then when I created first installed the wallet, I just copied the electrum wallet folder from my old pc (2 years ago) to my then new pc.

I tried installing electrum on my Android phone, but that one doesn't like my seed phrase, because my seed phrase has words which are not correct? My electrum seed phrase has 9 words. I understand that the word list is a limited list of words, and when I want to enter my first word, after entering the first letter, it disables some letters, I guess because with those letters it is not possible to create a valid seed phrase word. However, the second letter of my first word actually IS one of those disabled letters.

Reading more abot the seed phrase, I read a lot about 12 words en 24 words seed phrases but not about a 9 word seed phrase.

I also have an Exodus wallet from about the same age, with that wallet I did manage to install it on a new computer with the seed phrase.