https://en.wikipedia.org/wiki/Integer_factorization_records and https://en.wikipedia.org/wiki/RSA_numbers gives some pointers. Specifically, the latter describes a 768 bit key being factored "on December 12, 2009, over the span of two years", with CPU time that "amounted approximately to the equivalent of almost 2000 years of computing on a single-core 2.2 GHz AMD Opteron-based computer".

Later, in 2019, a 795 bit key was factored with CPU time that "amounted to approximately 900 core-years on a 2.1 GHz Intel Xeon Gold 6130 CPU. Compared to the factorization of RSA-768, the authors estimate that better algorithms sped their calculations by a factor of 3–4 and faster computers sped their calculation by a factor of 1.25–1.67."

So assuming the better algorithms transfer to smaller numbers, someone who knows how to use them (factoring big numbers seems significantly harder than just running CADO-NFS and pointing it at a number and a cluster) could probably do it in a couple months on a couple dozen modern machines.

For example, using the "795-bit computations should be 2.25 times harder than 768-bit computations" from the publication accompanying the second factorization, we could assume 900/2.25 = 400 Core-years of the Xeon reference CPU (which is 6 years old by now) would be needed to break the smaller key with the modern software. Two dozen servers with 64 equivalently strong cores each would need slightly over 3 months. Not something a hobbyist would want to afford just for fun, but something that even a company with a moderate financial interest in doing could easily do, provided they had people capable of understanding and replicating this work.