Welcome to the forum and congrats for mastering 3D printing to this point!
I’ll try to give a few answers to your problems, which however will be a bit generic. For more specific help I’d recommend that you post individual cases of your problems, ideally with photos. The community here is eager to help as good as they can!
- Stringing
In general many parameters can cause or mitigate stringing. Here are those I’m aware of:
- Humid filament: it seems the more moisture was accumulated by filament, the more it tends to create strings. Solution: Dry your filament - in the oven, a food dehydrator or in special devices (filament dryers) for that.
- Retraction settings: Filament retraction is a slicer setting which lets the print head pull back the filament a bit before travelling between two print locations. Playing with these settings can help getting better results.
- temperature, colling and print speed - all these parameters influence stringing. To get the best settings, there a test objects you can print to tune in your filament, e.g. a temperature tower.
- First layer adhesion
Unfortunately a not uncommon problem with the Sanpmaker 2.0 - the print bed often is bumpy. Some users are affected more, some less. Here’s a bit of additional information: Bed Leveling - Revisited & Detailed
But before you start that journey, perhaps check the “obvious”:
- Z-Offset: Make sure that your nozzle has the right height above the print bed. See e.g. here: Strings & boogers - #37 by Hauke
- Clean bed: The print sheet needs to be clean for good adhesion. Consider using warm water & dish soap to give your print sheet a jolly good cleaning ever once in a while. And/or use Isopropanol.
- Fine details
This is the most difficult to give general advice to - what are “fine details” to you? Especially here specific cases and photos would be helpful. I once printed a very detailed miniature - perhaps the settings there help you? Tabletop miniature with 0.2 mm nozzle and PVA support (Dual Extruder)
I general, for good details do not go too fast, make sure print cooling is on, and potentially avoid overheating of protruding parts: Overheating | Simplify3D Software
And of course a layer height of 0.2 mm limits your details. For very detailed prints you may want to go for 0.1 mm, or, as some slicers offer, use adaptive layer heights.
Bed adhesives: I personally used painter’s tape, glue stick and hair spray with success, but only found them useful on my previous printer that had a glass bed. On the Snapmaker print sheet IMHO PLA has a very good adhesion - if you have Z-.offset and bed levelling right.
Machine upgrades: For the single extruder print head, an additional print cooling fan is a considerable improvement. See this - unfortunately very unwieldy - thread: 3DP Part Cooling Fan 5015 Replacement for Gen 1 extruder
Hope this helps - happy printing!