This is not correct. The knighthoods which,should be included in Prefix and suffix are KG, KT, KP (which rank above Bt, which is not a knighthood but a Baronetcy), GCVO, KCVO, GCMG, KCMG, GCSI, KCSI, GBE, KBE, KCB, KB, and AK. Knights Bachelor have no post-nominal or suffix. OM, CH, PC, VC, GC etc are not knighthoods and therefore are not entitled to the prefix “Sir” but are definitely entitled to the suffix. A Baronet is entitled to the prefix and the suffix.
Wikitree is wrong to suppress prefixes and “nicknames” in name displays; this situation seems to have arisen because top table correctly did not want Dr and PhD both to be displayed. It is also wrong to say that suffix should include KG and KT but nothing else,
Bottom line: Sir and Knt is wrong.