OK, so 3 sessions ago, my Vengeance Paladin killed a young green dragon. I made a big deal of having him brag around town and to strangers he met, etc., that he killed a dragon, he started calling himself Hadrian "Dragonsbane" and Hadrian the Dragonslayer. I really played it up, and the party was playfully annoyed at his inflated ego.

Yesterday, my Paladin killed a young gold dragon (DM was not playing it as a Good creature) that was hunting the party down with his high level (like 15) Dragonborn Sorcerer mentor. The high level Sorcerer escaped and, while this is only a complication in the "main plot" of the campaign (which is our fight to end slavery in this world), I get the sense that the DM would add in more visits from him and/or more dragon stuff out of a sense of fun.

With the exp gained from yesterday's session, my Paladin is leveling to level 7 now. I suggested the possibility of being able to multi-class into a Draconic Sorcerer since I just killed 2 dragons in melee combat so close in time, and the DM was all for it.

I have decided to go all in, as level 6 Vengeance Paladin is an excellent time to break into Sorcerer for the multi-class, and it just makes for such a fun and organic story. Right now, my plan is to just level as Sorcerer as I gain more levels from now on. My original character goal was to explore playing a pure paladin through the higher levels. I've also been enjoying using Find Steed when able and am interested in getting Greater Find Steed later (need level 13 paladin for that). However, in addition to the mechanical benefits of a "Sorcadin" multiclass here, from an RP side, I cannot resist following the organic storyline and growing gold scales and gaining these magic powers.

My current level 6 Vengeance Paladin is a Variant Human with 16 Str, 10 Dex, 14 Con, 8 Int, 10 Wis, 16 Chr, and has the Polearm Master (PAM) and Sentinel feats already, and uses the Defense fighting style. I have a +1 Glaive, a Cloak of Protection, and normal Plate Mail. His AC is 20. He will be Paladin 6, Sorcerer 1 at our next session.

My role is the main tank of the group, which I do mostly by wearing plate and being controlling/sticky with PAM and Sentinel (and having a good offense as the best defense). For party make-up we have a Assassin Rogue who mostly likes to melee, an Evoker Wizard and Mystic who like to do fair amounts of support/debuffs from range, and a Life Cleric who's brand new to 5e and has been casting Bless but stayed at range healing a lot so far. We fight a mix of humanoids and monsters in our various combats.

I am looking for advice on my spell selection and on my tactics during combats for my newly developing Sorcadin. Having PAM and Sentinal, and in the role I play, adds some complications from the guides I have seen online.

Using the PAM feat for a bonus attack and also Sentinel makes several of the perks of a Sorcerer multiclass a little less useful. For example, normally both melee cantrips would work well on a Sorcadin. But while Booming Blade has positives combined with using a Polearm and metamagic quickened spell, that can also compete against Extra Attack (when not quickened), the PAM bonus attack when it is quickened and the Sentinel reaction movement effect (which looks like RAW it always happens when I hit with the reaction). Same goes for using Green Flame Blade, which combines well with the Elemental Affinity but is also competing with Extra Attack and the PAM bonus attack.

I am thinking of just skipping the melee cantrips entirely, or just adding Green Flame Blade after a few levels as an extra, when it can be a versatility if for some reason I cannot use a polearm. Because I am not including those melee cantrips, I am looking for advice on the spell selection and tactics I should pursue instead, for defense, buffing, and utility mostly. I mean, of course, I'll still take fireball, though!

I welcome your opinions. Thanks for reading and commenting.