Until recently, you needed to be a data scientist and a python developer mastering tens of libraries.
It is now easier with Hugging Face pipelines, or systems like Weaviate that completely hide the models.
But the real problem is now money.
You can find a Solr/Elasticsearch hosting service for €20/month.
For a WooCommerce client, self-hosting his small cluster on K8s was €100/month + the embeddings API costs.
WPSOLR + WooCommerce + AI search: https://www.wpsolr.com