The switch in the past year has been rather steady. No dramatic increases (though TOTK did boost Switch by about 2 million) and earns roughly 1 million sells per month gaining ~7 million since March 2023. Holiday Seasons for the Switch have been in decline losing about 1-2 million per year since 2020 (which was the biggest year for the Switch at 28.73 million), and last season earned it 8.22 million as seen from @ShadowLink93 recent post a couple hours earlier. And there is a new seasonal game that will be the most bought Holiday game this year (Super Mario Bros. Wonder).
Given this information I make an assumption that the Switch will sell approx. 7.3 million this holiday season, just below the 140 million mark.
Entering into 2024 it will be selling an average 1 million consoles per month. This will push the Switch to 147 million sales.
Entering into the Q3 of 2024 will be the release of the newest Nintendo console (unofficially codenamed Nintendo NG, for Nintendo Next Generation). We will see a steep decline in Switch sales. Maybe 3 million that holiday season. Bringing the Switch to 150 million.
Personally, I don't want a new console from Nintendo but I recognize that the technology is over 10 years old, and there are many signs as to the coming of a new generation of console:
-President Shuntaro Furuwaka states that "product launch won't happen before next spring at the earliest", this is in relation to the newest console in the works.
-Nintendo recently submitted a new patent that looks to be a DS with a detachable screen (maybe the next console?).
-Nintendo showcased their next console in a close door scenario with future developers
-Multiple developers have been given dev kits for the next generation of the Nintendo console.
Nintendo loves the Switch, they love the concept of "on the go" fun and even stated that the "Switch is just in the middle of its lifecycle and the momentum going into this year is good. The Switch is ready to break a pattern of our past consoles that saw momentum weakening in their sixth year on the market and grow further." (Can someone please explain how they think they are in the middle of the lifecycle for the Switch, this was in February 2022 the end of its 5th year). The Switch will break this pattern. This is how:
-Nintendo also stated that they will help bolster Switch sales “by supplementing existing titles with a continuous stream of new titles and add-on content.”
-This aligns with heir comment mentioning that "We are still working on software for the Switch for the fiscal year ending March 31, 2025".
-And based on past data when the Wii first was sold it was $249.99, when the WiiU released the Wii dropped to $129.99, which is a $100 drop, and when the 3DS released the DS dropped approximately $40. Meaning the Nintendo Switch V2 and OLED will receive a $100 drop when its successor releases, selling at $199.99, $249.99 respectively. And the Lite will sell at $149.99 with a $50 drop. So hopefully some people will see this drop in price and purchase more due to the expanded library, cheap cost, and extended content releasing until 2025.
From 2025 the Switch will be able to sell at least another 6 or 7 million reaching 157 million, and maybe the following year will sale another 2 or 3 million leading into 159 million, and 2027 will be its last selling year reaching 160 million. Let's a-go! 
Lifetime Sales Predictions
Switch: 160 million (was 120 million, then 140 million, then 150 million)
PS5: 130 million (was 124 million)
Xbox Series X/S: 54 million (was 60 million, then 57 million)
"The way to accomplish great things, is to be indefatigable and never rest till the thing is accomplished." - Joseph Smith Jr.
