Probably not? King Bubblie's Enhanced Senses may be getting a CRT to increase their effectiveness in all situations (TLDR, Orb users can always see what they're specifically looking for), which might totally negate Stealth Mastery.
But even if it doesn't, there's a list of issues. First of all she needs to back off to get into a position to hide. King Bubblie's range is FAR higher than Webby's, so there's no distance she'll realistically be able to back off at that King Bubblie won't be able to take ranged pot-shots at her until she's out of line of sight. Fight starting at 5 meters means it's going to be a lot of trouble unless she positions herself mid-fight near cover first. TLDR: Getting out of King Bubblie's range AND line of sight might risk attacks, especially Mass Attacks which would be extra bad.
And even if she gets into cover to hide, it's not like that gives her a massive advantage. She's still only slimly ahead in AP, so an ambush attack won't make a lot of progress, plus King Bubblie's range means it will always be in range to counter attack any attempts she goes for. Which again, a Mass Attack in revenge is going to hurt more and be harder to dodge, so if King Bubblie shoots that out Webby's not going to be having a good time.
Plus, while she might catch King Bubblie off guard without its forcefield once, King Bubblie's probably not going to be dumb enough to let that happen twice and start shielding more once it realizes what she's doing. Plus thanks to healing, it's going to be a slow grind to hit and run or set up ambush attacks to wear down an opponent who's durability is almost the same as her AP.
Webby's kinda delaying the inevitable, she's going to hit roadblocks dealing lasting damage, while always risking a decently stronger AOE explosion or a stray one-shot attack from Muscle Enhancement that could end the fight then and there in retaliation. Plus, she gets hit with a Mass Attack or a damage boosted ram or energy blast? She doesn't have King Bubblie's luxury of quick healing.