Saturday Themeless by Erik Agard

Erik's byline and enigmatic smile always means to get ready for an adventure and this puzzle did not disappoint. His grid-spanning center stacked block was very helpful.
I had a very unusual experience in that the SW corner had a lot of blanks at the end because of so many possibilities and my wrong take on Pacific in the down clue. Once I changed HAN Dynasty to QIN, that gave me QUARRELSOME and the SW cleared up as fast as I could type!
Across:
1. Point guard?: PEN CAP 😀 No basketball here.
7. Rihanna song with the lyrics "That was quite a show / Very entertaining / But it's over now": TAKE A BOW. ¯\_(ツ)_/¯ Unknown but the lyrics made sense quickly
15. Harlem theater: APOLLO - This theater and NASA's moon project use two "L's'" and skater Apolo Ono only uses one. It reminds me of Ogden Nash's silly poem
16. Upper management?: HAIR CARE 😀
17. Going from A to B, say: LINEAR - In plane geometry the shortest distance between two points is a straight line but not in curved geometry.
18. Far from fresh: OVERUSED - Even Erik could not avoid an OREO reference at 13 Down
19. Wave home: OCEAN 😀 Yeah, we baseball peeps thought of a third base coach signaling a runner to head for home
20. Uber around the Eiffel Tower?: TRES 😀 This finally occurred to me. Uber is German for "very" which is TRES in French.
21. Uncles, in Spanish: TIOS.
22. Save, in a way: DVR - DVR became a verb
23. China's first imperial dynasty: QIN - The Qin Dynasty (221-206 BCE) was the first imperial dynasty of China, establishing a centralized government and uniting the country after the Warring States period. I held on to HAN for a long time but it took over after only 20 years of the QIN Dynasty so...
19. Wave home: OCEAN 😀 Yeah, we baseball peeps thought of a third base coach signaling a runner to head for home
20. Uber around the Eiffel Tower?: TRES 😀 This finally occurred to me. Uber is German for "very" which is TRES in French.
21. Uncles, in Spanish: TIOS.
22. Save, in a way: DVR - DVR became a verb
23. China's first imperial dynasty: QIN - The Qin Dynasty (221-206 BCE) was the first imperial dynasty of China, establishing a centralized government and uniting the country after the Warring States period. I held on to HAN for a long time but it took over after only 20 years of the QIN Dynasty so...
24. 2, 4, and 24, e.g.: EVENS - I looked for a pattern but these were just random even numbers
26. Negative post?: PRE 😀 Erik! The opposite (negative) of "post" is PRE
27. Many a TV episode title: PUN - Here are some: 1. So Help Me Todd · 2. Better Off Ted · 3. Fawlty Towers · 4. Get Smart · 5. Schitt's Creek · 6. I Dream of Jeannie · 7. Grey's Anatomy · 8. Pawn Stars.
28. The Grand __ Opry: OLE.
29. Foreign exchange issue: LANGUAGE BARRIER - A fellow golf league member works in a packing plant where there are mostly Hispanic workers. He uses a device like this in verbal exchanges.
36. Imposition lead-in: I'M TERRIBLY SORRY.
37. Setting for Haiti: EASTERN TIME ZONE - Haiti has chosen to be on the Eastern Time Zone but its island mate, the Dominican Republic, has chosen to be in the Atlantic Time Zone.
44. "__ Explain Things to Me": Rebecca Solnit essay collection: MEN - She is given credit for coining the phrase "Mansplaining".
45. Paul with an axe: LES - Never mind Paul Bunyan, this axe is slang for a guitar and LES Paul invented the solid body electric guitar.
55. Not busy: AROUND - "Can you help me on Sunday?" "I'll be AROUND."
56. React slightly: BAT AN EYE.
57. Tutor's charge: MENTEE - Every student I taught was said to be a CHARGE of mine or my responsibility
Down:
1. Word for "stick" found in a Bay Area city name: PALO - Of course, PALO Alto means tall stick
2. "Shogun," for one: EPIC DRAMA.
4. "Let's be __": CLEAR.
5. "Reacher" star Ritchson: ALAN.
5. "Reacher" star Ritchson: ALAN.
7. Rose barb: THORN.
8. Dialectical source of "no cap" and "down bad," for short: AAVE ¯\_(ツ)_/¯ African American Vernacular English
10. Get it wrong: ERR.
11. Angle type: ACUTE.
12. Wide bowl: BASIN - Old hotels always had a BASIN and a chamber pot in the room. Uh, I'm only showing one of those.
13. Fried __: fair fare: OREOS - "Nutritional" info on a fried OREO
14. Commits to, in a way: WEDS.
20. Giving a bit of color: TINGING.
23. Pacific counterpart: QUARRELSOME
25. Knowledgeable: VERSED.
26. Ballet bend: PLIE.
27. Hand sanitizer brand: PURELL - Like DVR, it became a verb as in, "PURELL me."
28. Does as asked: OBLIGES.
30. Trick: GET.
31. Grocery payment meth.: EBT - Electronic Benefit Transfer
33. Put right: IRONED OUT - "I took the job once we got everything IRONED OUT"
34. Human rights activist Eckstein who is profiled in Season 4 of the "Making Gay History" podcast: ERNESTINE. ¯\_(ツ)_/¯
35. Some deli loaves: RYES.
41. Supreme Court name: SONIA and 43. Supreme Court name: ELENA - Vowel-rich jurists
42. Lowest-tier: WORST.
44. Sierra __: MADRE - Three separate ranges in Mexico
49. Focus of many fandom wiki pages: LORE.
50. Ye __ Shoppe: OLDE.
52. Trick: CON.
53. Cubano ingredient: HAM.
50. Ye __ Shoppe: OLDE.
52. Trick: CON.
53. Cubano ingredient: HAM.
