Against good players ur not going to get free throws so its very bad to base your game plan around throw combos. That works at lower level and online play, but wont cut it in tourney and local sessions.
Against Ragna, I usually IAD backwards or 2C to start.
2c is risky but a ton of ragnas love to start with hell's fang (214A) and youll usually get the counter hit.
Iad backwards is safer and u can feel them out. If they havent moved try a 2DD 214D~C and keep moving back. If you get the full screen you want proceed with 5DD and act parser pressure.
You can also mix in 214D~C if you feel bold enough. A good ragna player is usually gonna guess right at least once during the match and get u in the corner though. Don't freak out. Don't try to 2C , too much start up. if they're around the timer on-screen, throw out 3c. Around this distance you can do empty walk up and IAD over them out of the corner too. If this is done correctly even if they try to inferno divider you they will whiff going in the wrong direction. If they've closed in more than that try to barrier guard them back out a little to get a CCC off. You're just trying to make them block so you can get 6C and parser out. 6A can work if timed correctly between his strings and 2a2a2b3c 236D works as well. You can generally block low against pressure, his main launcher goes low first. The main 2 overheads one you should be able to block off reaction and the other one gauntlet hades is only a problem on reaction if they do the tiger knee version.
Every combo you should be getting in this matchup should be a minimum of around 3500 so you should be able to get advantages quickly. Try to save your burst if it is an advanced player as they will tend to go into blood kain setups under 10%. Burst will full screen them if they blood kain by you and you can 236236D their wake up and force a guessing game. Theres a ton of stuff but hard to include it all.