No. There has never been a Supreme Court case to lay definitive ground work on the third amendment. There has, however, been a significant number of lower court cases dealing with the 3rd Amendment.

The most recent is a case from Nevada, in which the court rejected the plaintiff's claims that the police constituted soldiers, and that a termporary 'taking' to achieve a tactical advantage did not constitute "quartering".

In the present case, various officers of the HPD and NLVPD entered into and occupied Linda’s and Michael’s home for an unspecified amount of time (seemingly nine hours), but certainly for less than twenty-four hours. The relevant questions are thus whether municipal police should be considered soldiers, and whether the time they spent in the house could be considered quartering. To both questions, the answer must be no.

here

The most significant group that might have had a 3rd Amendment claim were the Aleutian natives during the Japanese landings on the Aleutian Island chain in WW2. They were removed from their homes and placed in internment camps. However, a third amendment challenge was never brought and the federal government paid a sum to those who were removed much later (without an apology or recognition of fault). here

To directly answer your claim that:

in today's day and age the 3rd amendment isn't really needed

The most significant court case in dealing with the 3rd was decided by the Second Circuit of the US Court of Appeals in Engblom v Carey

In the absence of USSC guidance, it established certain holdings that the national guard are soldiers, the third amendment is incorporated, and the protection of the third amendment applies to those who do not own their home (renters, etc.) not just home owners.

It eventually found for the state in that state owned housing on prison grounds represented a special case of residency, but established a standard for 3rd amendment protections.

A good place to start, (and sadly addressing a period well outside this subreddit) is here addressing claims about contemporary 3rd amendment issues.

I can't answer your question about whether it as really ever needed as I primarily work with contemporary political questions, and I hope someone will be able to provide more information on that, but the court cases show that the third amendment is needed.