Just for the record in case you didn't know, Ult Disasters have 8 base Def. So they take lots more damage than basically all other content. Don't base your damage on them please~You probably should. Off-element, the damage bonus is 50% for a Full Burst (and 72.5% on-element). This means that a Uriel alone deals 2m damage, but a Uriel in a Full Burst deals effective 3m (or 3,45m on-element) damage. The same goes for all Hime. In general, unless you absolutely must, ALWAYS go for Full Bursts. Some "must" cases are stuff like murderous Overdrives going off that very turn, so you might as well Burst with what you have than die.
Now, Uriel has a massive Combo rate (dealing plenty damage per turn), and even a massive buff for more burst meter gain (gaining 17.5 burst per hit) so she's pretty much the first one ready to Burst first, AND even Bursts like a goddamn truck. So you might be asking, is Svarog even on the same tier as that bullshit?
And the answer is very much yes.
Awakened Svarog gives your entire team 40% permanent Assault. Not some 3/5 uptime 20% bullshit like Arthur, but 40% with full uptime (well, not available from turn1, but stacks up to 40% eventually). This is particularly good for new players (who still have low Assault), but is still noticeable even for veterans. In addition, Svarog is one of the few Hime that actually has a strong as fuck abilities. Effectively, in addition to Svarog's normal attacks, she also gains a double attack from ability damage. Usually Hime like this are fucked over by the damage cap and don't work like this in reality, but Svarog's damage cap is obviously typoed so it won't become a problem to anyone who isn't a whaliest of whales (your normal attacks need to be punching for 130k before you start having problems, but more like 150k). So effectively, on top of that 40% permanent Assault to the ENTIRE team, she also punches for 3-5 per turn. Every. Single. Turn. (on average)
So yeah, it's mostly a matter of preference. Whileas Uriel will usually punch 2-3 times per turn, it's just less than Svarog. However, Svarog won't let you skip entire phases of a fight. Oh, and I think the biggest whales of DMM have replaced Svarog now, with limited edition SOS-dan Haruhi. Not sure about Uriel's fate.Welp, that'd explain why you have so much shit...
Notice that as amazing as Sanahtlig's guide used to be, he just isn't as invested into the game as he used to be. As such, take it with a pinch of salt when it comes to upcoming content.
For the record, I think the rates in this game are so low that spending money on any non-guaranteed is a scam, but it's your money to spend. As for Fire SSR Amon, I'm not sure. My Fire team is weak enough that I haven't particularly cared to look into it, so hopefully somebody else will let you know if she's good for you or not.You have the best of the best right now, but all Light Hime are going to be crazy. As for which one would be right for you, well, hopefully somebody else will answer that.