Ying is an interesting pick in 2023 as she isn't crazy good but can excel if played right.
This is the build i use to heal, the play-style you want to use with it, will be to shatter as much as possible, and spam your ultimate. The rest is just positioning and playing with your team. For it to work you want to use clones around/next to corners as much as possible to your advantage. For items, i focus morale boost at the start until it is level 3 followed by chronos to level 3. These are interchangeable and can be bought in any order but i focus morale boost for the ult spam. After morale boost and chronos are level 3 i buy things to keep me alive e.g. haven and resilience, but it all depends on what the other team is playing.
Using her ability's may be a little overwhelming but it is quite simple. You want to be using your illusion and shatter as much as possible, with the main priority of illusions to take angles that can see your healing targets but not be seen by enemies, e.g. behind a corner/wall in front of your tank(s). You do not want to use your ult for nothing, but do not save it, treat it as a long cool down ability. The only other thing worth mentioning is to use your teleport when you're in danger e.g. you're getting flanked, or if you need to quickly reposition.
Shatter instantly Heals your target for 800, but its Cooldown is increased by 1s and it no longer explodes your Illusions. Reduce the Cooldown of Shatter by 2s if you miss.
Reduce the Cooldown of Shatter by 2.5s.
Increase the duration of your Illusions by 4s.
Increase the Health of each of your Illusions by 200.
Reduce your active Cooldowns by 2s after getting an Elimination.
Heal your Illusions for 40% of their maximum Health after activating Shatter.
Increase your Ultimate charge rate by 30%.
Reduce the Cooldown of all your abilities by 30%.
Reduce the Damage you take from Direct and Area of Effect attacks by 18%.
Ying's biggest synergy's lie within characters that can protect themselves from anti-healing mid-fight or just off fights. The only other way for these perks be utilized is for your team to play around corners and walls a lot more for easy fight disengages (to stop anti-healing). Rejuvenate is also one of the most important things for your teammates to purchase (yes even damages and flanks) as it counteracts anti-healing, which is one of Ying's biggest weaknesses due to it lowering her healing numbers significantly later in the game.
Make sure you are well positioned and aware of your surroundings at all times, as you will most likely be in your back line, in a prime position for flankers. This shouldn't be too much of an issue however as your damage should be in a position to cover you, paired with your teleport ability, you should be able to survive and keep the rest of the team alive.
There aren't really many bad characters to have on your team, however it will be harder to heal flanks as you most likely wont have much line of sight on them, but as long as they have rejuvenate, it will work out.