Is VoLTE not supported by default on GOS?

Yes and no. e.g. see https://grapheneos.org/usage#carrier-functionality

Wi-Fi Calling, VoLTE, Visual Voicemail, MMS, SMS, Calling and 5G (SA and NSA) all are supported, however some functionality may not be usable due to Google not supporting carriers on the stock OS officially or due to GrapheneOS not shipping proprietary apps required in order for this functionality to work on some carriers.

Generally 5G, SMS, MMS, Calls and VoLTE will work fine on GrapheneOS with officially supported carriers by Google.

Some carriers may restrict functionality, such as VoLTE, on imported Pixel devices as they only whitelist the IMEI ranges of Pixel device SKUs which were sold locally.

And https://grapheneos.org/usage#lte-only-mode

VoLTE / VoWi-Fi works on GrapheneOS for most carriers unless they restrict it to carrier phones.

So… it depends

If your carrier is official supported by google, your carrier itself supports it and your device is not imported, it is likely to work.

I thought the idea of cassette futurism is to show fictitious retrofuturistic tech. Specifically how 70s and 80s tech would look like in the (far-) future. and not how the actual tech looked in that time period, no matter how futuristic it looked back then.

What i expected to see was Alien and Blade Runner aesthetics and not GameBoy and Commodore. As it is now, it is simply “pictures of old tech”.

Well in germany you would get up to 3 years prison time for trying that bullshit. because it absolutely is animal abuse. quote the The German Veterinary Association for Animal Welfare

"A strictly vegan cat diet [would] be tantamount to an unauthorized, uncontrolled animal experiment and violates § 3 No. 10 of the Animal Welfare Act "

“Force-feeding for the purpose of an ideologically justified change of diet to vegetarian rations is a violation of § 3 No. of the Animal Welfare Act”