As far as SHR, RAID etc. are concerned, you are in the wrong place here, the appropriate forum for Synology NAS is e.g.
With regard to Syncthing, this is the right place. Therefore, first the question of which package you have installed and if that is known, is there a path to it, e.g.
which then contains all the information on the configuration that you have already mentioned. The complete content is to save as backup and, for example, restored to a new installation and the setup runs as before.
Now to the Synology SHR. The SHR is basically nothing more than a “variable” RAID that allows you to combine HDDs of different sizes to achieve the highest possible capacity. If you use the RAID for this, the smallest HDD determines the capacity yield. In a NAS with HDDs of the same size, SHR is therefore not necessary, RAID is the right choice. Basically, once SHR has been set up, it is no longer a hindrance, so switching to RAID has no advantages as far as I know. In this respect, you can leave it as it is.
There is another circumstance. If you delete a RAID or SHR, this is the same as deleting the storage pool. All data would be gone. If you have enough free storage outside the DS, it needs o transfer all the data in order to be able to reconfigure the HDDs on the DS.
But basically, the current constellation is better, because if one of the HDDs fails, you have the mirrored HDD and do not lose any data. Only to change the defective HDD is needed. Consider a HDD damage can always happen. In this respect, I hope you also make regular full backups just in case.