With the Byakugo, she definitely is a better team player, but I think her combat power peaked during the 2nd War.
The first thing to consider is the power of the Sannin. Most consider them stronger in their later years, but nobody explicitly says that. When Jiraiya uses Sage Mode, SPoP simply puts it down to his name as a Sannin, not something that goes above it. After the fight, they still only recognize him as a Sannin, nothing more. With Orochimaru, he considers himself weaker than Manda without his arms, which says that his new powers don't surpassed his old powers. With Tsunade, she is hyped as the difference maker among the Gokage for combat, but we see that she was not the clear cut best combatant among them. So based on these, it seems the Sannin did not reach new levels in later life.
The question, then, is how their new powers don't push them higher. That's simple. Orochimaru had lost his arms which he himself rates above his new powers, based on him considering Manda a strong threat without his arms. Jiraiya was an old man who had lost his speed, so Sage Mode only really served to return those high stats. Tsunade was an even older lady. The technique she uses makes her look young, but we're not told it actually rejuvenates her body. So those hits she delivers are old age hits, which logically should pale in comparison to what she could do in her youth. We know this from Hashirama directly comparing Sakura to a baby Tsunade, when Sakura had just delievered a hit ten times bigger than anything we've seen from old Tsunade. So it makes sense that Tsunade had also waned. So really, the old age (Naruto timeline) Sannin had lost much of their prime (2nd War) powers, so had these new powers to try to catch up to their old selves.
There's more evidence, such as SPoP expecting Jiraiya to easily deal with Animal Path in base, but Jiraiya himself expecting to die against it. In the case of Tsunade nd this thread, her 4th War version is even weaker than usual because she'd spent some time in a coma state and had only a few days of reserves in her Byakugo, compared to before the village attack during which she had 3 years of chakra in her seal.
The first thing to consider is the power of the Sannin. Most consider them stronger in their later years, but nobody explicitly says that. When Jiraiya uses Sage Mode, SPoP simply puts it down to his name as a Sannin, not something that goes above it. After the fight, they still only recognize him as a Sannin, nothing more. With Orochimaru, he considers himself weaker than Manda without his arms, which says that his new powers don't surpassed his old powers. With Tsunade, she is hyped as the difference maker among the Gokage for combat, but we see that she was not the clear cut best combatant among them. So based on these, it seems the Sannin did not reach new levels in later life.
The question, then, is how their new powers don't push them higher. That's simple. Orochimaru had lost his arms which he himself rates above his new powers, based on him considering Manda a strong threat without his arms. Jiraiya was an old man who had lost his speed, so Sage Mode only really served to return those high stats. Tsunade was an even older lady. The technique she uses makes her look young, but we're not told it actually rejuvenates her body. So those hits she delivers are old age hits, which logically should pale in comparison to what she could do in her youth. We know this from Hashirama directly comparing Sakura to a baby Tsunade, when Sakura had just delievered a hit ten times bigger than anything we've seen from old Tsunade. So it makes sense that Tsunade had also waned. So really, the old age (Naruto timeline) Sannin had lost much of their prime (2nd War) powers, so had these new powers to try to catch up to their old selves.
There's more evidence, such as SPoP expecting Jiraiya to easily deal with Animal Path in base, but Jiraiya himself expecting to die against it. In the case of Tsunade nd this thread, her 4th War version is even weaker than usual because she'd spent some time in a coma state and had only a few days of reserves in her Byakugo, compared to before the village attack during which she had 3 years of chakra in her seal.