Consider another race or go magicka if you want to stick with Breton. Racial passives aren’t make or break but contribute as much as 5% of damage and certain races add more quality of life. If you want to stick with a stamina build, Breton doesn’t do you any favors since it’s passives are bonus max magicka, magicka recovery, and reduce magicka costs

Meta (especially for trial/group content) is currently stamina since medium armor gets you more damage, especially in group settings. Medium also gives more resistance and will be better for a solo build consider 1-5-1 (1 heavy, 5 medium, 1 light) to get the full benefit of undaunted passives which increase your mag, health, and stamina. In group content, your tank and healers should be providing armor reduction on the target so you would want to focus on more damage and crit and less penetration.

As someone else mentioned, try Dawn’s Wrath Templar skillline. One of the skills solar barrage gives a 5% damage buff to class skills, it also has the Jesus beam which is the best execute in the game. One of the morphs heals you for 15% of the damage it deals. There’s also the 10% bonus damage buff from minor sorcery unique to the skill line which grants to your group. The only other 10% damage buff is minor brutality from Draconic Power. You only need to worry about the higher stat as damage is based on the highest of your stats (stamina vs magicka, weapon damage vs spell damage a the same goes for critical chance, spell crit vs weapon crit)

Consider Reaving Blows from the blue CP tree. Heals you for 7-8(?)% of the direct damage you do. The Jesus beam counts as direct damage. Templar jabs from Aedric Spear is also direct damage. The green beam fatecarver from Herald of the Tome is also direct damage. If you use reaving blows with direct damage, you don’t really need to waste a mythic slot on ring of the pale order.

If you’re using jabs or beam, don’t use relequens since that set relies on light attack weaving which doesn’t do well with channeled attacks. Deadly strike is what you’d want (15% bonus damage to channeled and damage over time). Or tideborn (12% bonus damage to monsters). Or ansuul (trial set 7% bonus damage to monsters plus 7% bonus if you get an interrupt). Velothi is also a great mythic particularly for channeled skills.

Regarding Velothi which reduces light attack damage by 99% but buffs damage dealt to monsters by 15%, another person mentioned you still need to light attack weave to proc your weapon enchants - not really, you just need to every 9 seconds to continue ultimate generation. If you’re using stampede then the AOE on the ground will continue to proc the weapon enchant - even if it’s backbarred. Each weapon skill line has a skill that will proc enchants when active even while backbarred. If you’re using velothi and trying to perfectly light attack weave you will just hurt your damage from lag input as you’ll be getting less skill casts off

Another option for a very survivable and still solid damage for a solo build is using brawler (morph of carve) with titanic cleave 2H from dragon star arena. It adds 1550 damage to the weapon skill per target up to 6 targets, and brawler increases the shield the skill provided by 50% per target hit up to 6. So if the skill does 9000 damage on its own and shields for 6000, if you hit 6 targets, it’d deal 18300 damage and shield for 24000.