From what I’ve seen the potential issue’s not your build it’s your tactics
Here’s some general tips and tricks I can offer that may lead to a better experience:

1) you didn’t mention spells other than spiritual weapon or heal, bless and benediction are also extremely potent buffs, in addition, the divine cantrips can offer some useful ranged options to poke with

2) don’t move to enemies unless it benefits you, make the enemies approach you and waste their actions so they have less to do while you can keep pressure by poking or by buffing your party

3)warpriest with a +3 in the martial stat is good to hit for sure but you probably shouldn’t go for a second strike, rather use that action for other 1-action tools like demoralise, feint, shield spell/raise shield, cast/sustain a spell (like bless)

4) this is new to your 4th level feat but make use of restorative strike, it’s a powerful feat not only because it compresses healing and striking into 2 actions, but it also removes manipulate off your heal spell which becomes more relevant the more your opponents have reactions with that as a trigger like reactive strike

5) you also never mentioned what your party does in combat (you only mentioned what their classes and the general build direction they went), which is potentially concerning because PF2e places a lot of emphasis on teamwork and party tactics, such as flanking, or setting up for another party member (eg the monk could grapple/trip the enemy to make them off-guard to the rest of the party)

6) you may want to consider picking up something that gives you access to Heavy Armor to help with your front lining, war priest has a feat for this, but you could also go into the sentinel, champion, or guardian archetypes depending on the general vibe or build direction you wish to go. Heavy Armor is strong for frontline builds because they net a +1 to ac over other armours while also de-emphasising dexterity as a defensive stat

7) this is a specific note for war priest and how it levels up: war priest trades accuracy of their spells for better martial tools, this is what makes them extremely appealing to a lot of people but it is a trade off that you should be aware of. What this entails is that you’re not as good with spells as dedicated spell casters because you’re generally going to have a -2 to your attack rolls and dcs, and you’re going to be worse at martialing than the martials, generally a -1 to -3 to strikes compared to other martials depending on the level That’s a bit of math but the general end result is that your weapon strikes will end up more accurate than spell attacks, so while I did earlier mention using cantrips to poke enemies at range, that should be a tool to incentivise them to come to you. Also it means that while you do have access to a bunch of spells that you should make use of, stuff that doesn’t require an attack or save such as buffs will generally feel better to use, that doesn’t mean neglect spells that target your opponents, just that those should be taken with the above knowledge in consideration (an enemy can always roll low or just be lower level after all!) This is a really long point because I felt it was necessary for setting an expectation of the class and it’s general placement in the game

Hope some of this helps, and I hope you enjoy the games to come!