I've successfully installed Ventura on a 2013 iMac 21.5", and I must say, the patcher has performed remarkably well. This post has prompted me to consider updating to Sonoma.
On another note, I'm contemplating upgrading the storage to an SSD from its existing HDD. A local tech service offers a 1TB SSD upgrade for AUD$400, which is quite cost-effective given the specs - a quad-core i5 processor with 8GB RAM. This upgrade promises to significantly extend the useful life of an already solid little machine.