Neoprene is a strange beast its hardness is similar to a relevant EVA pr PU foam but it absorbs a lot i.e its open cell so don't use super glue, its rigid and wicks into the neoprene, sets and gives you a big patch of hard ridged sponge that just tears around its edge.The 3m5200 or Sika flex would be soft yes ok but again makes a big blob with a weak edge, quick grip or other MEK glues (shoe goo etc) work and are soft but bloody messy and ugly. Most surf shops sell set suit repair kits with a dedicated glue that is the Goldielocks not too stiff not to soft, just right, formula perfect for neoprene, and its black. The same as manufacturers use to glue wetsuits, stubby coolers etc etc. The iron-on patches do surprisingly well and last a lot longer than you would think, so protect the damage after the repair.
$25 bucks gets you a kit and is less than sika flex or 3m!
oceanandearth.com.au/products/surf-accessories-ultimate-wetsuit-repair-kitPS plenty of you tube vids on repairs too....