1. Optical modules now it’s very affordable https://www.fs.com/products/11552.html
2. More stable and without any limitations (for example 1500 MTU on S+RJ10 and other)
3. On my opinion S+RJ10 has a lot other problems - overheating, length and type of cable, cooper connector on front and etc.
We use many CRS317 on backbones, data centers and clients with big external storages. Handle without problem heavy traffic > 100Gbps and hundreds of VLANs.
Use SwOS 2.7 and not upgrade it till MikroTik fix all known bugs. Before use it update to latest available RouterOS and upgrade firmware too, after that switch it to SwOS. (That fix FANs firmware on switch).
If you plan to use RouterOS for switching be sure that you know how to do it (double check the manuals) and there is known bug with port flapping on 10G links with CRS328 and TX/RX pauses with other MikroTik switches with 10G ports.