What is you research area? If you are good at self study I would recommend 2 Esri reference books. GIS Tutorial for ArcPRO 2.6 and Getting to Know Web GIS, 4th edition. ou can further suppliment these books with Learn GIS lessons. In all probability, neither of these will be a substitute for an instructor led class, whether it be face to face or hybrid online. You may also find a free MOOC class.