Why don't you want a catalog? The SQL or REST catalogs are pretty light to set up. I have my eye on lakekeeper[0], but Polaris (from Snowflake) is a good option too.
PyIceberg is likely the easiest way to write without Spark.
We did an evaluation of various REST catalog options and went with Open Catalog from Snowflake (a Polaris-based managed service that works independently from their data warehousing solution). Lakekeeper is nice - it's one of the few catalogs with FGAC and table maintenance.
PyIceberg is nice but we had to drop it because it's behind Java API and it's unclear when it will match up, so depending on which features are needed I'd look it up
PyIceberg is likely the easiest way to write without Spark.
0 - https://github.com/lakekeeper/lakekeeper