What is the meaning of the ending in the Personal Shopper (2016) film?

I just watched it. I cannot figure it out.

1. Who killed Kyra? If it's all Maureen's doing, then it doesn't make sense that Ingo confessed to the killing. He also acted very guilty when cops approached him outside the hotel. So let's say Ingo killed Kyra.

2. Who texted Maureen? Most of the reviews I read said it was Ingo. I find it unlikely that he knew every little detail of Maureen's schedule. He had no reason to tell her to come to the hotel either. In one of the text the stalker said he had her spare keys. Ingo might be a super creep but I don't know how he could obtain them. Also, if he planted the Cartier stuff in her apartment using those keys, he would want them to stay in her place.

3. Who booked room 329? It cannot be Lewis since he's a ghost and he cannot pay for it. It's not Ingo either since there's nothing he could gain by luring in Maureen (and possibly kill her there) It has to be Maureen.

4. Then why did Ingo come out of 329? Did Maureen invite him? Why? Only if she wanted to frame Ingo for the murder. Then again, wasn't Ingo the killer?

I cannot reason with the plot. Another thing I find fishy is her boyfriend. He looks quite sickly and Maureen doesn't get to see him in person when she goes to Oman. Does he really exist? He kinda looks like Lewis' ghost that popped up in the kitchen.

I'm going with a straight forward fact pattern. Lewis (the ghost) wants to protect his sister. He gets her out of the murder scene and he protects her in the Rm#329 scene. Maureen gets (maybe returns ?) the jewlery, ( uses it to join BF? She is certainly dressed better on her "vacation"?) Inglo doesn't want it (evidence) but he does want to make sure all his text messages are erased. Which Maureen did by changing the simm card and showing him, no need to kill Maureen & incur a second murder. I agree it's a bit odd that we don't see Maureen leave the hotel but we do see Lewis, the protecting ghost, leave. Next scene Maureen in bar so she's not dead!! The last scene is quixotic but understandable. Lewis is OK but still worried about his sister. If Maureen does not want Lewis around, & not have him worrying about her, she has to look inside herself & get over his death.

The door Ingo said to meet Maureen at is 329 the one he's seen walking out of, the door Maureen enters in the hotel doesn't need a key card and has no number on it. She could have realized the one texting her was Ingo from the fact the text said they had spare keys and since Maureen has keys to Kyras place why wouldn't Kyra have keys to Maureen's?

So he could have stolen them and Kyra was dead so it couldn't have been her, maybe she planned to meet up with police to give the jewelry over to them after saying Ingo planted it at her place and wants to meet her at the hotel. The noise could have been police entering the hotel room since Maureen didn't act startled or scared at the sound of the opening and closing door and she freaked out every time something or someone came up out of nowhere I doubt she'd lay down and die from hearing the door open and close. That'd make sense to why she never was seen leaving the hotel and that two under cover police were outside of the hotel.

The invisible person was probably her brother who may have had something to do with the hotel set up somehow and he was leaving but nothing is really clear on why there were scenes of a invisible person leaving the floor of the hotel and then the hotel. Maybe the purpose was so we'd create our own ending.

I don't understand the ghost thing at the end of the movie though it could of been the spirit who attacked her and possibly followed her around copying the glass dropping which Maureen probably felt was her brother that dropped the glass but wouldn't admit it to herself so if a spirit was copying her brothers glass drop and want to give her hope its him but really wants to make her think shes lost it. I don't know.